U.  S.  DEPARTMENT   OF  AGRICULTURE, 

BUREAU  OF  ANIMA.L  INDUSTRY.— BULLETIN  No.  38. 

A.  D.  MELVIN,  CHIEF  OF  BUREAU. 


TUBERCULOSl^3 


J     >J>\ 


OF   THE 


FOOD-PRODUCING  ANIMALS. 


BY 


D.  E.  SALMON,   D.  V.  M. 


WASHINGTON: 

GOVERNMENT    PRINTING   OFFICE. 
1906. 


ORGANIZATION  OF  THE  BUREAU  OF  ANIMAL  INDUSTRY. 


Clii.'i':   A.    D.    .MKI.VIN. 

'xtu/il  ( 'liii'f:  A.   M.    KAKHINIITON. 
r/,,Y;  r/,-,-/.-.-  M.   I1..  J..XKS. 

/>«/;•//  IHi'lxioit:   Kn.    II.  WKHSTKK,  chief;  CI.AKKNCI:   I'..    I, AM-:,  assistant  cliief. 
Iitx/H-rtioii  I)  rttilvn:  KICK  I'.  STKDDO.M,  chief;   I",  (i.  IlorcK,  associate  chief:   .Moimis 
\VOOHKN,  assistant  chief. 

Quarantine  Division,    HICIIAKD  \V.    Hi<  K.MAN,  chief. 
Animal  Husbandman:  <;KOK^K  M.   KOMMKI.. 
l-'.ililnr:  JAM  KM  M.    I'ICKKNS. 
Aftixt:   \V.   S.    I).    HA  INKS. 
/.i/iruriiiii:   UKATKICK  C.   <  MUCHLY. 

I.AIioKATOKIKS. 

Dirixiun;  MAKION   I >OKSKT,  chief. 

lUriximi:  JOHN  II.  MOHLEH,  chief. 
Zoological  Division:  I'KAYTON  II.   HANSOM,  chief. 

EXPERIMENT    STATION. 

E.  C.  SCHKOKDKK,  superintendent;  W.  K.  COTTON,  assistant. 

MEAT    INSPECTION. 

//(  charge. 

Milwaukee,  Wis.— Dr.  A.  E.  Behnke,  room  .I:;L> 
Federal  Building. 

Nashville,  Tenn.— Dr.  TV.  B.  Lincoln,  care  Ten- 
nessee Packing  and  Provision  Company. 

National  Stock  Yards,  111.— Dr.  J.  B.  Clancy. 

Nebraska  City,  Nebr.— Dr.  W.  H.  Gibbs.  care  Mor- 
ion -(iregson  Company. 

Newark,  N.  J.— Dr.  A.  F".  Martins,  can-  Swift  it 
Co..  Harrison  station. 

New  Haven, Conn.— Dr.  Albert  Long,  caresperry 
&  Barnes. 

New  York,  N.  Y.— Dr.  H.  N.  Waller,  lull  West 
Forty-second  street. 

Oklahoma,  Okla.— Dr.  Raymond  Johnson.  P.  o. 
box  ]L'Sf>. 

Oltumwa,  Iowa.— Dr.  Joshua  Miller,  care  John 
Morrell  it  Co. 

Philadelphia,  Pa.— Dr.  C.  A.  Si-haulier,  I:il  South 
Second  street. 

Pitt-burg,  Pa. — Dr.  F.  W.  Ainsworth,  Union 
Stock  Yanls. 

Portland,  Oreg. — Dr.  Clarence  Loveln'rry,  room 
402  custom-house  i  new  ). 

Quincy,  111.— Dr.  J.  S.  Kelly,  care  Blomer  it 
Michael  Co. 

St.  Louis.  Mo.— Dr.  J.  J.  Brougham,  care  Mis-ouri 

Stock  Yards  Company. 
San  Diego.  Cal.— Dr.  Robert  Darling,  care  Charles 

S.  Hardy. 
San   Francisco,  Cal. — Dr.  (ieorge  S.  Baker,  care 

Western  Meat  Company. 
Seattle,  Wash.— Dr.  <  >.  B.  I  less,  care  Frye-Bruhn 

Company. 
Sioux  Falls.  S.  Dak.— Dr.  Herman  Busman,  care 

Sioux  Fall-  Packing  Company. 
Sioux  City,  Iowa.— Dr.  (I.  A.  Johnson.   Kxchange 

Building. 
South  Omaha.  Nebr.— Dr.  DonC.  Aver.  P.>-t  oilier 

building. 

South  St.Joseph,  Mo.— Dr.  (ieorge  Ditewig. 
South  St.  Paul.  Minn.  Dr.  F.  D.  Ketchum. 
Titeoma.  Wash.  — Dr.  K.  C.  Joss,  care  Car-tens 

Parking  Company. 
Toprka.  Kans.— Dr.  F.  L.  De  Wolf,  can-    Charles 

WollV  Packing  Company. 
Waterloo,  Iowa.-  Dr.  T.  W.  Scott,  can-  The  Rath 

Packing  Company.  • 

Wichita.  Kan-.     Dr.  W.  N.  Neil. care  John  Cudahy 

Company. 
Worcester,  Mas«.— Dr.    I-:.    I'.-Dowd,  care  White, 

Pevey  it  Dexter  Co. 

page  3  of  cover.] 


Arkansas  City,  Ark.— Dr.  R.  W.  Tuck,  care  Hen- 
neberry  it  Co. 

Ausiiii.  Minn.— Dr.  M.  o.  Anderson,  cure  Goo.  A. 
llorincl  it  Co. 

Baltimore,  Md.— Dr.   H.  A.  Hedrick,  :>15  St.  Paul 
street. 

Blooming-ton,  111. — Dr.  Frederick  Braginton,  earq 
Continental  Packing  Company. 

Boston,  Ma-s._ Dr.  .).  F.  Ryder.  141  Milk  street. 

Bright  wood.    Mass.— Dr.    \\ .    .).    Murphy,    care 
Springfield  Provision  Company. 

BulYalo.  N.  V.— Dr.  B.  1'.  Wende,  Live  Stock  Ex- 
change Building.  Kasi  BntTalo. 

Cedar  Rapid-.  Iowa.— Dr.  T.   A.   Shipley,  care  T. 
M.  Sinclair  cV  Co. 

Chicago,  111.— Dr.   S.    E.    Bennett,   room  310  Ex- 
change Building,  I'lnon  Stock  Yards. 

Cincinnati,  Ohio.— Dr.  A.  <;.  (i.  Kiehardson,  care 
Union  stork  Yards. 

Cleveland,  Ohio.— Dr.  E.  P.  Sehaflter,  care  Cleve- 
land Provision  Company. 

Davenport,  Iowa.  — Dr.  E.  I>.  Bertram,  care  Henry 
Kohrs  Packing  Company. 

Deliver.    Colo.  — Dr.    W.    K.    Howe,    care  Western 
Packing  Company. 

DCS    Moincs.  Iowa.  — Dr.  Cliester  Miller,  care  The 
Ai.rar  Packing  Company. 

Dt-iroit.  Mich.— Dr.  I,.  K.  (Jrecn.care  Hammond, 
Standish  tv  Co. 

Kan  Clain-,  \Vis.-Dr.  (i.   W.    Butler,  cure  Driim- 
inond  Brothers. 

Fort  Worth,  Tex.— Dr.  A.  H.  Wallace,  care  Swift 
&Ci>. 

Hutchinson.    Kan>.     1'r.    .1.    K     Black  well,   care 
Hiitrhinson  Packing  Company. 

Indianapolis,  Ind. — Dr.  N.  C.  Soreiiseti,  care  Kin- 
gan  ,v  Co. 

Jersey  city,  N.  .).— Dr.  Julius  Huelseu,  care  The 
J'T-"\  City  Slock  Yard  Company. 

s  City,  Kan--.  — Dr.   L.    R.    Baker,    room  :;::s 
I-ive  Slock  Kxchange. 

Lafayette.  Ind.— Dr.  J.  E.  Cloud,  care  Kern  Pack- 
ing Company. 

Los  Angeles.  Cal.— Dr.  A.  K.  Rishcl,  care  Cudahy 
Packing  Company. 

Louisville,  Ky.— Dr.   II.    II.  (k-orge,   ."K)7  Johnson 
street. 

Mankato.  Minn.— Dr.  H.  H.  Dell,  care  Macbeth  A 
Gardner, 

ManballtOWn,   Iowa.— Dr.     J.    ().   F.    Price,    care 
Brittain  it  Co. 

city,  Iowa. — Dr.  Robert  Jay,  care  .laeoli  ]•'.. 
Decker  &  Sons. 

[(Continued  on 


Pjoqerty  of  the  United  States 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY.—  BULLETIN  No.  38. 
A.  D.  MELVIN,  CHIEF  OF  BUREAU. 


TUBERCULOSIS 


OF   THE 


FOOD-PRODUCING  ANIMALS 


BY 

D.  E.  SALMON,  D.  V.  M. 


WASHINGTON: 

GOVERNMENT    PRINTING   OFFICE. 

1906. 


LETTER  OF  TRANS/VUTTAL. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY, 

Washington,  D.  C.,  May  31,  1906. 

SIR:  I  have  the  honor  to  transmit  herewith  a  paper  on  Tuberculosis 
of  the  Food-Producing  Animals,  by  Dr.  D.  E.  Salmon,  late  Chief  of 
this  Bureau,  who  was  especially  engaged  by  you  to  prepare  the  same. 
I  recommend  the  publication  of  the  paper  as  Bulletin  No.  38  of  this 
Bureau. 

Animal  tuberculosis,  though  not  nearly  so  prevalent  in  the  United 
States  as  in  most  European  countries,  is  nevertheless  a  serious  prob- 
lem and  a  menace  to  our  live-stock  industry,  and  is  also  regarded  as  a 
distinct  source  of  danger  to  human  health.  Its  infectious  nature  and 
the  means  for  its  repression  should  be  fully  understood,  and  earnest 
and  intelligent  efforts  should  be  made  with  a  view  to  its  ultimate  erad- 
ication from  this  country. 

The  bulletin  treats  the  subject  in  a  very  comprehensive  manner  and 
reviews  some  of  the  more  important  experimental  work  which  has 
served  to  establish  the  facts  and  conclusions  presented.  The  author 
is  a  recognized  authority  on  the  subject  with  which  he  deals,  and  the 
bulletin  is  written  in  the  light  of  the  latest  scientific  knowledge.  The 
discussion  of  two  phases  of  the  tuberculosis  problem  which  have 
received  particular  attention  in  recent  years — the  relation  between  the 
human  and  bovine  forms  of  tuberculosis  and  the  protection  of  cattle 
against  tuberculosis  by  immunization — should  be  of  especial  interest 
at  this  time. 

Respectfully,  A.  D.  MELVIN, 

Chief  of  Bw\-a  « . 

Hon.  JAMES  WILSON, 

Secretary  of  Agriculture. 


CONTENTS. 


Page. 

Introduction 5 

Part  I. — Material  facts  concerning  tuberculosis - 7 

The  prevalence  of  tuberculosis 7 

Extent  of  the  disease  in  the  United  States 7 

Meat-inspection  statistics 7 

Conditions  shown  by  tests  of  herds 8 

Relations  of  contagion  and  environment  to  spread  of  the  disease 10 

Tuberculosis  in  British  herds 11 

Conditions  on  the  continent  of  Europe 13 

The  losses  from  tuberculosis 14 

The  nature  of  tuberculosis 16 

Effects  upon  the  organs  of  the  body 16 

Symptoms 21 

Effects  upon  a  herd  of  cattle 23 

An  experiment  with  tuberculous  cattle 23 

Spread  of  tuberculosis  by  dispersion  sale 25 

Histories  of  affected  herds 26 

The  cause  of  tuberculosis 27 

The  tul >e role  bacillus 27 

Manner  of  infection  and  development  of  the  disease 29 

Infectiveness  of  milk  of  tuberculous  cows 31 

Spread  of  tuberculosis  from  diseased  to  healthy  cattle 37 

The  effect  of  insanitary  conditions 38 

The  detection  of  tuberculosis 41 

Physical  examination 41 

The  tuberculin  test 46 

P^xamination  of  the  carcass 52 

Immunization  of  cattle  against  tuberculosis 53 

Early  experiments 54 

McFadyean's  experiments 56 

Work  of  Pearson  and  Gilliland 58 

Von  Behring's  investigations 60 

Experiments  by  Hutyra 63 

Thomassen's  experiments 64 

Klimmer's  investigations 66 

Work  of  Koch  and  others 67 

ValU'e's  experiments 69 

Conclusions  regarding  immunizatio n 71 

The  curative  effect  of  treatment  with  tuberculin  and  with  attenuated 

tubercle  bacilli 71 

Animal  tuberculosis  and  the  public  health 73 

Early  views 73 

Identity  of  human  and  bovine  tuberculosis  questioned 74 

Investigations  by  the  German  commission 75 

Investigations  by  the  German  Imperial  health  olHiv 76 

Conclusions  now  generally  held  by  scientists 78 

3 


4  ILLUSTKATIONS. 

Page. 

Part  II. — The  repression  of  tuberculosis .7 79 

Measures  that  may  be  adopted  by  individuals 79 

Prevention  by  avoiding  known  causes  of  tuberculosis 79 

Eradication  of  tuberculosis  from  the  farm 81 

The  Bang  method  of  eradicating  tuberculosis S2 

A  modification  of  the  Bang  method 83 

Successful  treatment  of  a  Wisconsin  herd 84 

Eradication  from  a  Connecticut  herd 85 

Recommendations  of  Regner,  of  Sweden . 86 

Immunization  in  connection  with  the  Bang  method 87 

Destruction  of  reacting  animals  and  creation  of  a  sound  herd 89 

State  aid  for  the  eradication  of  tuberculosis it  1 

Federal  cooperation  for  the  eradication  of  tuberculosis 94 

Bibliography 97 


ILLUSTRATIONS. 


Page. 

PLATE  I.  Lungs  of  a  healthy  hog 16 

II.  Tuberculous  lungs  of  hog 16 

III.  Portions  of  tuberculous  lungs  from  cattle 16 

IV.  Fig.  1. — Tuberculous  spleen  of  hog.     Fig.  2. — Spleen  of  healthy  hog. 

V.  Tuberculous  liver  of  cow 20 

VI.  Tuberculous  pericarditis  of  cow 20 

VII.  Fig.   1. — Tuberculous  intestine  of  a  child.     Fig.  2. — Tuberculous 

ovary  of  cow 20 

VIII.  Tuberculous  udder  of  cow 20 

IX.  Tuberculous  lymphatic  gland  of  cow 20 


TUBERCULOSIS  OF  THE  FOOD-PRODUCING  ANIMALS. 


INTRODUCTION. 

There  are  few  if  any  subjects  connected  with  animal  husbandry 
upon  which  more  has  been  written  and  published  within  recent  years 
than  tuberculosis.  It  has  been  discussed  in  the  publications  of  the 
Bureau  of  Animal  Industry,  in  the  bulletins  of  many  experiment 
stations,  in  the  reports  of  live-stock  sanitary  boards  and  State  veteri- 
narians, and  in  the  columns  of  the  agricultural  press.  The  scientific 
investigations  in  relation  to  it  have  been  extfemely  numerous  and 
important  in  their  results.  Notwithstanding  this  activity  in  the  dis- 
cussion and  investigation  of  the  disease,  however,  there  is  probably 
no  subject  upon  which  there  is  a  greater  difference  of  opinion  among 
the  owners  of  live  stock,  and  none  of  which  the  importance  is  so 
inadequately  appreciated. 

It  is  unfortunate  that  in  the  first  attempts  to  control  this  disease  in 
the  United  States  measures  were  adopted  by  some  of  the  State  authori- 
ties which  were  so  radical  and  harsh  that  they  aroused  the  antagonism 
of  the  cattle  owners,  the  men  who  above  all  others  should  have  been 
aided  and  benefited,  and  that  a  spirit  was  developed  in  the  contests 
that  followed  which  has  made  it  extremely  difficult  to  obtain  a  dispas- 
sionate and  impartial  consideration  of  the  measures  that  are  required 
to  relieve  our  farmers  from  the  losses  which  they  are  now  suffering 
because  of  the  existence  of  this  disease  and  to  remove  the  danger  of 
the  far  greater  losses  with  which  they  are  menaced.  A  disease  so 
widespread  can  not  be  controlled  unless  those  most  interested  in  the 
live  stock  of  the  country  give  their  active  support  to  the  undertaking. 
It  is  therefore  wise  to  examine  the  subject  in  an  unbiased  manner,  to 
study  carefully  the  nature  of  the  disease,  to  learn  as  nearly  as  possi- 
ble what  the  losses  are,  to  what  extent  these  losses  are  liable  to  increase, 
and  whether  measures  of  repression  are  or  are  not  advisable.  It  is 
not  a  question  of  sentiment,  but  one  of  fact,  and  it  should  be  exam- 
ined as  a  business  proposition. 

The  object  of  this  bulletin  is  to  present  the  facts  in  as  clear  and  con- 
cise a  manner  as  possible,  giving  the  observations  and  views  of  the 
best  authorities,  and  of  those  who  have  studied  the  problem  longest 
and  are  most  competent  to  express  an  opinion.  These  facts  should  be 
known  and  considered,  and  if  it  appears  that  the  prosperity  of  the 
live-stock  industry  is  threatened,  or  that  serious  losses  are  occurring, 
appropriate  action  may  be  taken  to  check  the  losses  and  to  remove 

their  cause. 

5 


6  TUBERCULOSIS    OF    THE    FOOD-PRODUCING  .ANIMALS. 

Although  tuberculosis  is  an  extremely  .insidious  disease,  which  may 
enter  the  herd  by  an  unsuspected  channel  and  develop  to  alarming 
proportions  before  its  presence  is  suspected,  it  is  nevertheless  a  pre- 
ventable disease  and  one  the  control  of  which  may  now  be  undertaken 
with  every  prospect  of  success.  But  to  control  or  eradicate  tubercu- 
losis it  is  necessary  to  have  a  clear  comprehension  of  the  peculiarities 
of  the  disease,  of  its  cause,  of  its  nature,  of  its  mode  of  extension,  of 
its  detection.  It  is  one  of  the  problems  which  could  not  be  handled 
without  the  aid  of  science;  but  now  that  science  has  come  to  the  relief 
of  the  owner  of  live  stock  and  has  shown  him  how  this  plague  may  be 
managed  successfully,  he  is  in  a  position  to  avail  himself  of  this 
knowledge  and  to  adopt  such  measures  as  may  be  required  both  to 
stop  the  losses  which  it  is  now  causing  and  to  guard  against  its  reap- 
pearance in  the  future. 

It  is  difficult  to  imagine  anything  more  discouraging  or  disastrous 
to  the  plans  of  the  young  breeder  than  to  discover  that  in  bringing 
together  the  foundation  elements  of  his  herd  he  has  introduced  the 
infection  of  this  disease,  which  counteracts  his  efforts  to  build  up 
a  great  herd  and  gradually  exhausts  his  capital.  Nor  is  the  case 
any  the  less  serious  when  the  infection  is  introduced  into  a  herd 
already  established  and  developed  by  the  labor  and  the  study  of  the 
best  years  of  the  breeder's  life.  How  many  breeders  have  been 
rendered  penniless  by  the  ravages  of  the  tuberculosis  bacillus;  how 
many  priceless  animals  have  been  destroyed  by  it;  how  man}^  precious 
strains  of  blood  has  it  weakened  or  annihilated! 

And  finally  there  is  the  influence  of  the  tuberculous  herd  upon  the 
community.  A  herd  of  animals  is  not  bred  simply  for  the  entertain- 
ment and  use  of  the  breeder,  but  the  primary  object  is  to  produce  and 
sell  dairy  products,  meat,  and  breeding  animals  to  other  people.  Is  it 
right  to  sell  a  tuberculous  animal  to  go  into  another  breeder's  herd  when 
the  disease  is  likely  to  be  carried  by  that  animal,  to  spread,  and  to  dam- 
age or  destroy  that  herd?  Is  it  right  to  sell  tuberculous  cattle  or  hogs 
for  slaughter  when  we  know  that  many  of  these  animals  are  slaughtered 
in  establishments  where  there  is  no  inspection  and  that  the  diseased  car- 
casses may  consequently  be  used  for  human  food  ?  Is  it  right  to  sell  the 
milk  from  tuberculous  herds  knowing  that  it  may  be  used  for  the  nour- 
ishment of  the  inost  delicate  children,  when  such  milk  frequently  if  not 
generally  contains  the  tuberculosis  bacillus  which  finds  its  way  to  it 
both  through  the  udder  of  the  diseased  cow  and  the  dust  of  the  stable? 

These  questions,  serious  from  both  a  moral  and  a  financial  point  of 
view,  confront  the  breeder  of  the  present  day.  There  can  be  no 
question  that  the  great  body  of  breeders  desire  to  do  what  is  right, 
and  it  would  appear,  therefore,  that  when  a  practicable  plan  of  han- 
dling tuberculosis  is  demonstrated  to  them  they  will  not  hesitate  in 
adopting  it,  but  will  rapidly  suppress  this  disease  and  eradicate  it 
from  their  herds. 


PART  I.— MATERIAL  FACTS  CONCERNING  TUBERCULOSIS. 


THE  PREVALENCE  OF  TUBERCULOSIS. 

EXTENT   OF   THE    DISEASE    IN   THE    UNITED   STATES. 

Tuberculosis  is  the  most  serious  disease  of  animals  with  which  the 
American  farmer  is  confronted.  It  is  the  most  prevalent  disease  of 
cattle,  and  is  becoming  very  common  with  swine.  It  exists  in  all  parts 
of  the  United  States,  even  in  the  Rocky  Mountain  region,  but  is  most 
frequently  seen  in  dairy  cattle  and  in  hogs  that  have  been  raised  in 
dairy  districts.  Unfortunately  it  has  also  been  allowed  to  propagate 
itself  extensively  in  some  of  the  most  valuable  beef  breeds,  as,  for 
example,  the  Shorthorn  and  the  Angus,  and  its  frequency  in  other 
varieties  of  cattle  appears  to  be  increasing. 

MEAT-INSPECTION    STATISTICS. 

The  statistics  of  tuberculosis  in  this  country  are  fragmentary,  and 
give  but  an  imperfect  idea  of  the  actual  condition,  though  we  have 
sufficient  to  show  that  it  is  not  as  prevalent  as  in  some  of  the  countries 
of  Europe.  In  the  meat-inspection  service  of  the  Bureau  of  Animal 
Industry  the  number  and  percentage  of  carcasses  condemned  during 
the  last  five  \7ears  is  shown  in  the -following  table. 

Number  of  carcasses  of  cattle  and  hogs  inspected  and  the  number  condemned  for  tubercu- 
losis during  the  years  1901-1905. 


Cattle. 


Hogs. 


Year. 

Number  of 
carcasses 
inspected. 

Number 
of  car- 
casses 
con- 
demned. 

Per  cent 
of  car- 
casses 
con- 
demned. 

Number  of 
carcasses 
inspected. 

Number 
"of  car- 
casses 
con- 
demned. 

Per  cent 
of  car- 
casses 
con- 
demned. 

1901  

5,219,149 

6,454 

0.10 

24,  642,  753 

8,650 

0.035 

1902  

5,  559,  %9 

7,944 

.14 

25,277,107 

14,927 

.059 

1903  

6,134,410 

8,598 

.14 

21,793,788 

20,  299 

.092 

1904 

6  350  Oil 

1£>  173 

.16 

24,128,462 

34,656 

.143 

1905  

6,  0%,  597 

10,  956 

.18 

25,  323,  984 

64,919 

.256 

This  table  does  not  show  the  total  number  of  animals  affected  with 
tuberculosis,  for  in  many  cases  only  a  part  of  the  carcass  was  con- 
demned, and  probably  in  a  still  larger  number  of  cases  the  disease  had 
progressed  so  slightl}T  that  the  entire  carcass  was  passed  as  fit  for 
human  food.  These  milder  cases  of  disease  are  not  included,  as  cor- 
rect statistics  of  them  are  not  available. 

7 


8 


TUBERCULOSIS    OF    THE    FOOD-PRODUCING    AM  MA!.-. 


Tuberculosis  in  sheep  is  a  rare  disease,  and  in  most  cases  appears  to 
be  the  result  of  infection  from  bovine  sources.  There  were  but  27 
carcasses  of  sheep  condemned  by  inspectors  of  the  Bureau  of  Animal 
Industry  on  account  of  tuberculosis  during  the  fiscal  year  1905,  out 
of  7,872,671  animals  inspected  at  the  time  of  slaughter.  The  nodular 
disease  of  the  intestines  (caused  by  the  parasite  (Eaophagostomum  colum- 
lianum)  and  caseous  lymphadenitis  are  far  more  frequent  and  are 
often  mistaken  for  tuberculosis  by  persons  not  thoroughly  familiar 
with  the  distinctive  characteristics  of  these  diseases. 

CONDITIONS    SHOWN    BY    TESTS    OF    HERDS. 

In  1901  Doctors  Russell  and  Hastings,  of  the  Wisconsin  Agricul- 
tural Experiment  Station,  published  a  review  of  the  tests  of  cattle 
with  tuberculin  which  had  been  made  in  the  United  States,  and  from  this 
review  the  following  summary  has  been  made,  which  is  valuable  on 
account  of  showing  the  wide  distribution  of  tuberculosis  rather  than 
indicating  the  proportion  of  cattle  affected  in  the  respective  States.1" 

Results  of  the  tuberculin  tests  of  cattle  in  various  States. 


State. 

Number 
tested. 

Number 
tubercu- 
lous. 

Per  cent 
tubercu- 
lous. 

Vermont  ...            .                                        

60,000 
24,685 
4,093 
6,300 
947 
1,200 
34,000 
2,500 
929 
3,655 

2,390 
12,  443 
1,080 

3.9 
50.0 
26.4 
14.2 
6.9 
18.4 
14.1 
21.4 
12.0 
15.3 
13.0 
11.1 
13.8 

35.6 
9.0 

•       32.5 
2.2 

Massachusetts  '  

Massachusetts,  entire  herds  

Connecticut          ..                             .                                      

New  York,  1894  

66 
163 
4,800 

New  York,  1897-98  

Pennsylvania  

New  Jersey  

Illinois,  1897-98 

Illinois,  1899  

560 

Michigan  

Minnesota  

3,430 

Iowa  .,  

873 

323 
935 

688 
3,421 

122 

115 
84 

191 
76 

Wisconsin: 
Experiment  station  tests  — 
Suspected  herds                                  .                                        ... 

Nonsuspected  herds  

State  veterinarian's  tests  — 
Suspected  herds                                                 *       ... 

Tests  of  local  veterinarians  under  State  veterinarian  on  cattle 
intended  for  shipment  to  States  requiring  tuberculin  certificate  . 

The  State  veterinarian  of  Pennsylvania,  Dr.  Leonard  Pearson, 
thinks  that  not  over  2  per  cent  of  the  cattle  of  that  State  are  tubercu- 
lous; and  probably  if  a  general  test  of  all  the  cattle  of  the  other  States 
mentioned  were  made  we  should  find  a  very  much  smaller  proportion 
tuberculous  than  is  indicated  by  the  above  tabular  statement.  The 
explanation  of  the  high  percentages  that  have  been  given  is  found  in 
the  fact  that  it  has  been,  for  the  most  part,  suspected  herds  which 
have  been  tested.  Admitting  that  the  greater  part  of  these  percent- 
ages are  too  high,  they  nevertheless  reveal  a  very  serious  condition. 

In  a  report  on  Tuberculosis  of  Cattle,  Pearson  and  Ravenel*  say 
that  it  has  been  found  by  testing  herds  that  the  percentage  of  tuber- 

oThe  figure  references  are  to  bibliography  at  end  of  bulletin. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS. 


9 


culosis  varies  from  0  to  100  per  cent,  and  there  are  instances  of  many 
large  herds  in  which  nearly  all  of  the  animals  have  been  infected.  As 
examples  of  such  herds  found  in  Pennsylvania  the  following  are  cited: 


Herd. 

Number 
of  cattle 
in  herd. 

Number 
of  tuber- 
culous 
cattle. 

Per  cent 
of  cattle 
found 
tubercu- 
lous. 

Herd. 

Number 
of  cattle 
in  herd. 

Number 
of  tuber- 
culous 
cattle. 

Per  cent 
of  cattle 
found 
tubercu- 
lous. 

1 

174 

166 

95.4 

8 

61 

45 

73  8 

2  T.  

73 

59 

80.8 

9  

18 

16 

88.8 

3 

22 

17 

77.3 

10 

13 

10 

76  9 

4 

14 

14 

100.0 

11 

15 

10 

66.6 

5  .     .   .              

63 

37 

58.7 

12  

59 

53 

89.8 

6 

67 

37 

55  2 

7 

20 

20 

100.0 

Total 

599 

484 

80.8 

These  figures  of  course  represent  extreme  and  exceptional  conditions. 
Of  all  the  tuberculous  herds  tested  with  tuberculin  under  the  auspices 
of  the  State  live  stock  sanitaiy  board,  about  13  per  cent  of  the  animals 
have  proven  to  be  afflicted  with  tuberculosis. 

Russell 3  says  this  disease  is  the  most  devastating  animal  plague  with 
which  Wisconsin  farmers  have  to  contend.  Of  the  70  herds  examined 
by  the  State  live  stock  sanitary  board  for  the  years  1903  and  1904,  49 
were  found  affected.  Very  frequently  only  a  small  number  of  react- 
ing animals  were  found,  but  the  appended  list  shows  some  startling 
cases  of  widespread  infection. 

Instances  of  widespread  infection  of  herds  that  have  been  tested  in  Wxconsin  during 

1903-4. 


Number 

Number 

Number 

Number 

Date  of  examina- 

of ani- 

found 

Per  cent 

Date  of  examina- 

of ani- 

found 

Per  cent 

tion. 

mals  in 

tubercu- 

affected. 

tion. 

mals  in 

tubercu- 

affected. 

herd. 

lous. 

herd. 

lous. 

December  16,  1902.. 

16 

12 

•75 

January  5,  1905  .. 

27 

21 

77 

April  6,  1903  

39 

27 

69 

January  25  1905 

38 

23 

60 

May  5,  1903. 

33 

20 

60 

February  5  1905 

14 

12 

85 

May  11,1903... 

36 

20 

55 

February  12  1905 

60 

14 

23 

June  2,  1903  

28 

16 

57  i 

March  20  1905 

20 

13 

65 

June  3,  1903  

121 

24 

20 

April  20  1905 

22 

20 

91 

October  22,  1903.... 

56 

25 

44 

April  25,  1905.... 

30 

17 

57 

December  9,  1903... 

49 

24 

49  ; 

Mav  3,  1905  

31 

21 

69 

March21,1904  

55 

27 

49 

May  8,  1905  . 

92 

31 

33 

March  31  1904 

26 

15 

57 

April  17,1904... 

30 

23 

76 

Total 

853 

428 

50 

October  26,  1904.... 

30 

23 

76 

If  such  widespread  infection  as  these  examinations  indicate  were 
found  in  all  herds  the  stock  interests  of  the  country  would  be  on  the 
verge  of  bankruptcy,  and  yet  the  record  above  presented  does  not 
give  by  any  means  all  of  the  cases. 

A  brief  list  of  infected  herds  which  have  been  more  or  less  careftill}' 
studied  is  useful  in  showing  the  extent  to  which  the  disease  develops 
under  the  best  conditions  of  sanitation,  and  in  indicating  the  difficulty 
of  building  up  a  herd  of  good  cattle  even  under  skillful  supervision 
unless  the  healthfulness  of  the  herds  from  which  the  purchases  are 
made  has  been  ascertained. 


10 


TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 


Herd  of— 

Number 
In  herd. 

Number 
tubercu- 
lous. 

Percent 
tubercu- 
lous. 

Maine  State  Agricultural  College  (1886)  4  

51 

61 

100  0 

Soldiers'  Home,  Washington,  1).  C.6  

63 

53 

84  1 

Government  Hospital  for  tlie  Insiuu',  Washington,  D.  C.°  

102 

79 

77.0 

Massachusetts  Agricultural  College7  

82 

25 

78  1 

New  Jersey  Agricultural  Experiment  Station8  

42 

25 

59  5 

Kansas  Agricultural  College  9  

66 

15 

26.  H 

Wisconsin  Agricultural  Experiment  Station  10  

30 

26 

M;  c 

Connecticut  Agricultural  College,  Storrs  Experiment  Station  n  

49 

19 

•38.8 

Colorado  Agricultural  College1-  

31 

10 

XI  'I 

Vermont  Agricultural  Experiment  Station                ...                   .  . 

33 

21 

63  6 

Ohio  Agricultural  Experiment  Station,  first  test  1:)  
Texas  Agricultural  Experiment  Station  
Louisiana  Agricultural  Experiment  Station  '•*                                    .  ... 

30 
21 

22 

14 
10 

7 

46.  G 
47.6 
31  8 

New  Hampshire  College  of  Agriculture  and  the  Mechanic  Arts'*  

55 

10 

18  2 

New  York  (Geneva)  Agricultural  Experiment  Station1'  

27 

15 

55.5 

Utah  Agricultural  Experiment  Station  'J 

18 

13 

72  2 

New  Mexico  Agricultural  Experiment  Station  '8  . 

19 

3 

15.8 

Central  Experimental  Farm,  Ottawa,  Canada  1!>  

38 

21 

55.3 

RELATIONS   OF   CONTAGION   AND    ENVIRONMENT   TO   SPREAD   OF   THE 

DISEASE. 

While  bad  sanitary  conditions  undoubtedly'  favor  the  spread  of 
tuberculosis  it  is  not  preeminently  a  disease  of  poor,  neglected,  under- 
fed scrub  cattle,  for  the  better  class  of  cattle  have  suffered  from  it  to 
an  even  greater  degree.  It  has  been  constantly  imported  with  pure- 
bred stock,  and  has  consequently  been  introduced  into  the  best  herds 
and  has  extended  from  these  to  the  dairy  herds  and  common  cattle. 

The  beef  cattle  coming  to  our  markets  are  still  remarkably  free  from 
tuberculosis,  but  the  disease  appears  to  be  increasing  among  this  class 
of  animals,  as  is  indicated  by  the  percentage  of  condemnations  in  the 
meat-inspection  service.  There  appears  to  be  no  climate  and  no 
method  of  handling  cattle  which  entirely  arrests  the  spread  of  the 
disease.  This  is  shown  by  its  existence  upon  the  ranges  of  our 
Western  States,  and  to  an  even  greater  extent  in  the  herds  of 
Argentina,  Australia,  and  New  Zealand.  Considering  that  these 
cattle  live  in  the  open  air  and  in  climates  that  have  been  considered 
remarkably  favorable  for  people  affected  with  tuberculosis,  we  can 
not  but  be  impressed  with  the  importance  of  avoiding  the  use  of 
tubercular  breeding  stock  and  thus  guarding  against  the  dissemination 
of  this  contagion. 

There  are  some  portions  of  the  world — as,  for  example,  the  northern 
parts  of  Norway  and  Sweden,  the  steppes  of  Russia,  Iceland,  and  parts 
of  Africa  and  South  America — where  tuberculosis  is  said  to  be  quite 
rare.  The  cattle  of  the  Island  of  Jersey  appear  to  be  free  from  it. 
This  seems  to  have  been  true  of  the  common  or  native  cattle  of  many 
countries.  In  the  United  States  there  are  numerous  sections  where 
the  original  stock  of  cattle  has  been  bred  without  much  admixture 
with  the  improved  breeds  and  where  few  outside  cattle  have  been 
introduced.  These  sections  are  generally  free  from  tuberculosis.  It 
has  also  been  observed  in  Argentina  and  other  countries  that  this  dis- 
ease is  unknown  among  the  native  cattle,  but  that  it  has  been  intro- 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  11 

duccd  with  the  improved  breeds  from  Europe,  and  is  now  common 
with  both  purebreds  and  grades.  It  is  even  held  by. Professor  Bang 
that  tuberculosis  was  brought  to  Denmark  in  the  first  half  of  the  nine- 
teenth century  by  cattle  from  Switzerland,  Schleswig,  and  England, 
and  that  this  method  of  distribution  may  now  be  seen  in  Sweden  and 
Norway,  particularly  through  the  introduction  of  English  cattle. 

These  facts  confirm  the  conclusions  from  scientific  observation  and 
experimentation  that  tuberculosis  develops  only  by  infection  from 
some  existing  case  of  the  disease;  and  that  it  will  be  possible  in  the 
future,  as  it  has  been  in  the  past,  for  a  section  or  a  State  to  raise  cat- 
tle that  are  free  from  it. 

TUBERCULOSIS   IN    BRITISH    HERDS. 

The  British  herds  appear  to  be  justly  chargeable  with  much  of  the 
tuberculosis  of  cattle  and  swine  which  now  exists  in  many  parts  of  the 
world.  The  unparalleled  skill  of  the  British  breeders  in  developing 
useful  and  superior  breeds  of  animals,  and  particularly  of  beef  cattle, 
long  since  attracted  the  attention  of  the  world  and  led  to  the  diffusion 
of  this  improved  blood  through  the  herds  of  many  countries.  But, 
unfortunately,  the  breeders  of  Great  Britain  were  not  as  skillful  in 
avoiding  tuberculosis  as  they  were  in  increasing  the  size,  perfecting 
the  form,  and  hastening  the  maturity  of  the  animals,  and  the  result 
has  been  not  only  that  they  unwittingly  propagated  the  disease,  but 
that  they  distributed  it  in  the  most  extensive  manner. 

It  would  not  be  correct  to  assume,  however,  as  some  have  been 
inclined  to  do,  that  Great  Britain  is  the  source  from  which  has  been 
derived  the  tuberculous  infection  of  all  other  lands,  for  the  equal  or 
greater  prevalence  of  the  disease  in  some  other  countries,  notably  in 
German}7,  France,  Holland,  and  Belgium,  indicates  an  infection  not  less 
remote.  It  is  probably  true  that  there  were  infected  localities  in  all 
these  countries,  and  that,  with  the  improvement  of  the  means  of  com- 
munication and  the  development  of  commerce,  the  exchange  of  cattle 
became  more  frequent,  so  that  the  infection,  which  had  previously 
been  limited  to  a  few  small  districts,  was  everywhere  distributed.  At 
that  time  the  nature  of  the  disease  was  not  well  understood,  and  for 
many  years  its  existence  in  the  larger  part  of  the  affected  animals  was 
not  even  suspected.  It  was  therefore  quite  natural,  when  the  advance- 
ment of  scientific  knowledge  made  it  possible  to  detect  tuberculosis 
readily,  and  when  the  disease  was  found  to  affect  a  large  proportion  of 
the  cattle,  to  charge  imported  cattle  with  its  introduction. 

Nevertheless  there  are  man}'  cases  in  which  the  introduction  of 
tuberculosis  may  be  clearly  traced  to  British  cattle,  and  among  these 
may  be  cited  the  herds  of  Canada,  of  the  United  States,  of  Argentina, 
of  South  Africa,  of  Australia,  and  of  New  Zealand.  That  the  herds 
of  England  and  Scotland  are  badly  infected  there  is  ample  proof. 


12 


TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 


The  testing  of  the  Queen's  herd  at  Windsor  some  years  ago.  and  the 
unexpected  discovery  that  86  out  of  40,  or  90  per  cent,  were  affected 
and  that  some  of  them  were  in  a  very  advanced  .stage  of  disease  aroused 
public  interest  in  the  subject  and  brought  out  much  information.  The 
returns  from  testing  cattle  with  the  tuberculin  supplied  by  the  Royal 
Veterinary  College,  as  stated  in  March,  1900,  showed  that  among 
15,392  animals  tested  4,105,  or  26  per  cent,  reacted.  Taking  the  vari- 
ous tests  made  of  which  records  are  at  hand  there  is  an  aggregate  of 
20,930  head  examined,  of  which  5,441,  or  26  per  cent,  were  pronounced 
tubercular. 

That  some  of  the  best  purebred  herds  of  Great  Britain  are  badly 
infected  is  known  by  the  results  of  testing  with  tuberculin  cattle  from 
such  herds  in  the  quarantine  stations  on  this  side  of  the  Atlantic,  and 
also  by  testing  cattle  which  were  desired  for  shipment  to  the  United 
States.  The  following  table  shows  the  number  of  cattle  tested  by  the 
United  States  inspector  stationed  in  Great  Britain  and  the  number 
that  were  rejected: 


Year. 

Number 
of  cattle 
tested. 

Number 
rejected. 

1901        .                                                                   

161 

18 

1902                                                                                  

1,067 

139 

1903  

631 

98 

1904  

239 

87 

1906  

23 

11 

Total                                         ,                                                                           .   . 

2  131 

303 

Of  the  purebred  cattle  which  were  to  be  imported  into  the  United 
States  during  the  years  from  1901  to  1905,  inclusive,  14.2  per  cent 
reacted;  but  this  is  not  a  true  indication  of  the  proportion  of  animals 
in  these  herds  affected  with  tuberculosis,  since  only  those  animals  were 
offered  which  were  supposed  to  be  in  condition  to  pass  the  test  suc- 
cessfully. It  must  also  be  admitted  that  the  more  or  less  frequent 
testing  of  the  animals  in  these  herds  has  reduced  the  proportion  of 
animals  which  react.  The  percentage  of  tubercular  animals  in  these 
herds  is,  therefore,  without  doubt  considerably  greater  than  the  per- 
centage of  reactions  obtained  by  the  inspector. 

The  proportion  of  reactions  to  tuberculin  obtained  with  different 
breeds  of  animals  is  interesting  as  indicating  to  some  extent  the  rela- 
tive infection  of  the  different  breeds;  although,  owing  to  the  compar- 
atively small  number  of  animals  covered  by  the  tests,  conclusions  from 
these  figures  should  not  be  too  absolute.  The  following  table  shows 
the  number  of  animals  of  each  of  the  principal  breeds  tested  and  the 
number  and  percentage  which  reacted: 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS. 


13 


Breed. 

Number 
of  ani- 
mals 
tested. 

Number 
of  ani- 
mals 
which 
reacted. 

Per  cent 
of  ani- 
mals 
which 
reacted. 

Ayrshire  

52 

16 

30.7 

Aberdeen-Angus                                                       .                 .        

390 

108 

27.7 

Shorthorn  ....             

248 

60 

24.2 

Jersey  

366 

24 

6.8 

Galloway                                                                                        

114 

6 

5.2 

Hereford  

417 

17 

4.1 

CONDITIONS   ON    THE    CONTINENT   OF    EUROPE. 

The  frequency  of  tuberculosis  among  domesticated  animals  on  the 
continent  of  Europe  is  generally  admitted.  The  statistics  which  reach 
us  from  there  are  somewhat  fragmentary,  but  sufficient  to  demonstrate 
the  gravity  of  the  situation. 

In  France  Professor  Nocard  estimated  that  in  the  regions  of  Brie 
and  Beauce  approximately  25  per  cent  of  the  cattle  were  tubercular, 
while  the  cattle  of  Auvergne  and  Limousin  (exporting  districts)  were 
free  from  the  disease.  In  Brittany,  Niyernais,  Upper  Vosges,  in  the 
southeast,  and  in  certain  valleys  of  the  Pyrenees,  the  disease  affects 
from  25  to  50  per  cent  of  the  cattle. 

In  Holland  the  percentage  of  tuberculous  cattle  found  among  those 
slaughtered  in  Amsterdam  gradually  increased  from  1.7  per  cent  in 
1888  to  13  per  cent  in  1898,  while  the  proportion  of  swine  affected 
increased  from  1.47  per  cent  in  1895  to  3.58  per  cent  in  1898. 

The  percentages  of  tubercular  cattle  found  in  the  slaughterhouses  of 
Prussia  and  Saxony  are  shown  by  the  following  table: 


Year. 

Prussia. 

Siixony. 

1895  .  .  . 

11.4 

27.28 

1897  

15.8 

1399  .   . 

14  4 

29  76 

1902  

16.4 

30.98 

In  some  of  the  cities  the  percentage  has  been  even  greater;  for  ex- 
ample, Berlin,  1902,  25.35  per  cent;  Breslau,  1902,  34.67  per  cent; 
Leipsic,  1902,  36.16  per  cent;  Zwickau,  1902,  36.27  per  cent;  Zittau, 
1902,  41.24  per  cent.20 

In  Sweden,  according  to  Regner,21  there  were  tested,  during  the 
years  1897-1904,  226,864  head  of  cattle,  of  which  (59,717,  or  30.7  per 
cent,  reacted. 

In  Norway,  Bang2*  states  that  according  to  Malm  there  had  been 
tested,  up  to  the  beginning  of  1902, 131,995  cattle,  of  which  8,029,  or 
6.1  per  cent,  reacted.  In  Finland,  during  the  years  1894-1900,  75,447 
cattle  were  tested,  the  proportion  of  reactions  being  13.7  percent,  and 
according  to  the  official  statistics  21,994  were  tested  in  1903  and  5.6 
per  cent  reacted. 


14 


TrKKRCFLOSIS    OK    THK    KoolM'KolHTl  N<!     ANIMALS. 


Iii  Denmark  the  results  of  the  tuberculin  tests  and  of  the  efforts  to 
control  the  disease  have  been  extremely  interesting.  Bang22  has 
recently  reported  the  complete  statistics  of  this  work  in  that  country, 
as  follows: 

Result*  of  tuberculin  lest»  of  cattle  in  Denmark  from  1893  to  1904. 


Period. 

Farms. 

Number 
of  ani- 
mals 
tested. 

Number 
of  ani- 
mals re- 
acting. 

Per  cent 
of  tested 
animals 

reacting. 

Total. 

First 
testing. 

April   1893  to  June  1894  

327 
1,873 
930 

|  7,316 

1,454 
1,293 
1,101 
695 
895 
646 
738 

327 
1,645 
749 
/  3,012 
\  2,165 
618 
543 
417 
259 
396 
213 
277 

8,401 
44,902 
20,791 
84,897 
65,788 
35,  533 
33,568 
26,  078 
18,818 
23,347 
19,364 
23,164 

3,362 
17,303 
6,  622 
21,668 
lfi.C.12 
7,725 
6,759 
4,976 
2,857 
3,531 
2,875 
3,750 

40.0 

38.5 
31.9 
25.5 
23.8 
21.7 
20.1 
18.0 
15.2 
15.1 
14.8 
16.2 

June,  1894,  to  October,  1895  

October,  1895,  to  May,  18%  

May  1896  to  June  1897  . 

June  1897,  to  May  1898  

Mav,  1898,  to  January,  1899  

Year  1899  

Year  1900                                            

Year  1901                      

Year  1902  

Year  1903  

Year  1904                  .           

Total 

17,268 

10,  621 

404,651 

97,070 

24.0 

The  proportion  of  tuberculous  swine  found  in  the  slaughterhouses  of 
some  of  the  German  cities  is  interesting  as  showing  the  extent  to  which 
the  disease  may  develop  among  this  class  of  animals.  The  statistics 
with  reference  to  these  findings  are  presented  below: 


City. 

Year. 

Per  cent 
of  tuber- 
culous 
swine. 

City. 

Year. 

Per  cent 
of  tuber- 
culous 
swine. 

Berlin... 

1895 

3.09 

Magdeburg  

1902 

5.19 

Do                              .... 

1899 

4.01 

Potsdam  .                              

1900 

7V55 

Do  

1902 

5.40 

Zittau  

1902 

6.35 

Danzig 

1898 

5.66 

Zwickau 

1896 

6.06 

Do                                

1902 

5.49 

do..  .               

1899 

3.89 

Magdeburg  

1896 

1.91 

do  

1902 

3.41 

1898 

3.55 

It  is  plain  that  tuberculosis  is  far  less  frequent  in  the  United  States, 
with  both  cattle  and  hogs,  than  it  is  in  Europe;  but  it  also  appears 
from  the  rate  of  increase  shown  by  the  statistics  of  various  parts  of  the 
world,  including  our  own  meat-inspection  reports,  that  unless  its  dis- 
semination is  by  some  means  checked  it  will  require  but  a  few  years 
for  it  to  gain  the  same  headway  here  that  it  has  acquired  there. 

THE  LOSSES  FROM  TUBERCULOSIS. 

It  is  a  difficult  matter  to  estimate  with  any  approach  to  accuracy  the 
losses  from  a  disease  like  tuberculosis,  concerning  which  the  statistics 
are  incomplete  in  every  respect.  There  are  now,  however,  approxi- 
mately 11,000  carcasses  of  beef  and  65,000  carcasses  of  hogs  condemned 
each  }Tear  by  the  Federal  meat  inspectors  on  account  of  tuberculosis. 
We  should  not  be  far  wrong  in  estimating  the  loss  on  these  carcasses 
at  present  prices  as  $40  each  on  the  beef  and  $12  each  on  the  pork. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  15 

We  should  therefore  have  as  the  net  annual  loss  from  the  condemna- 
tion of  carcasses  $440,000  for  beef  and  $780,000  for  pork,  or  a  total 
of  $1,220,000.  This  statement,  however,  does  not  include  the  647 
parts  of  beef  carcasses  and  the  142,105  parts  of  hog  carcasses  which  it 
was  necessary  last  year  to  condemn  for  the  same  cause,  and  the  approxi- 
mate value  of  which  can  not  be  ascertained. 

In  addition  to  the  carcasses  condemned  by  the  Federal  inspectors, 
there  are  a  considerable  number  condemned  by  State  and  municipal 
inspectors.  These  are  mostly  carcasses  of  daily  cattle  killed  in  the 
work  of  suppressing  tuberculosis,  or  of  cows  no  longer  profitable  in 
the  dairy  which  are  sent  for  slaughter  to  the  smaller  abattoirs.  The 
aggregate  number  of  these  has  not  been  ascertained,  but  in  some  years 
it  has  amounted  to  several  thousand  carcasses. 

The  losses  to  the  dairy  industry  from  tuberculosis  have  been  enor- 
mous from  decrease  in  milk  and  depreciation  and  death  of  animals. 
The  dairy  herds  have  been  affected  to  a  greater  extent  than  any  others, 
and  the  infection  has  as  a  rule  spread  through  the  cows  of  a  herd 
until  50  to  80  per  cent  of  the  animals  were  affected.  In  the  early 
stages  of  the  disease  the  product  of  the  cows  is  not  visibly  lessened, 
but  as  the  tubercular  process  develops  the  animals  often  become 
feverish,  their  milk  is  diminished  in  quantity,  and  they  lose  flesh  and 
are  no  longer  profitable.  The  losses  from  shrinkage  of  the  milk  and 
from  the  destruction  of  so  many  cows  must  be  tremendous,  but  it  has 
never  been  definitely  determined. 

An  extremely  serious  phase  of  this  subject  is  the  effect  of  the  dis- 
ease in  destroying  valuable  families  of  cattle  and  blood  lines  which 
can  never  be  renewed.  In  most  of  the  breeds  there  are  certain  families 
or  strains  of  blood  which  have  been  developed  by  long  and  skillful 
selection  and  Avhich  represent  the  one  marked  success  in  a  breeder's 
life.  The  representative  animals  of  such  a  strain  are  generally  few  in 
number  and  may  all  be  in  one  herd.  Under  such  circumstances  the 
introduction  of  tuberculosis  has  often  meant  the  annihilation  of  the 
strain  and  the  blotting  out  of  the  achievements  of  a  lifetime  of  toil 
and  study.  Such  losses  can  scarcely  be  measured  in  dollars  and  cents, 
but  they  are  no  less  real  and  no  less  serious  as  an  obstacle  to  the 
development  of  the  cattle  industry. 

The  losses  to  the  breeders  of  purebred  beef  cattle  have  also  been 
and  still  are  so  great  as  to  merit  the  most  serious  consideration.  When 
the  individual  animals  of  a  herd  are  worth  hundreds  or  even  thousands 
of  dollars,  the  introduction  of  a  fatal  infectious  disease  may  soon 
cause  the  loss  of  a  fortune,  and  this  is  just  what  has  occurred  upon 
many  a  breeding  farm.  Such  a  danger,  always  present  and  always 
menacing  an  industry,  must  discourage  individual  efforts  and  do  much 
to  prevent  the  attainment  of  lasting  prosperity. 

The   influence  upon   our  export  trade  of   regulations   relative   to 


16  TUBERCULOSIS    OF    THK    F<><H)-1'K()DUOINO    ANIMALS. 

tuberculosis  will  probably  become  more  and  more  unfavorable. 
Breeding  and  daily  cattle  for  Canada  and  Argentina  must  now  be 
tested  and  found  free  from  the  disease  before  they  will  be  admitted. 
The  tendency  everywhere  is  to  make  more  stringent  regulations,  and 
any  considerable  increase  in  the  prevalence  of  the  disease  would  have 
an  unfavorable  effect  upon  the  sale  of  live  animals,  meats,  and  dairy 
products,  even  if  burdensome  regulations  were  not  imposed.  To  meet 
successfully  the  increasing  competition  in  the  markets  of  the  world  it 
is  important  to  have  products  which  it  can  be  shown  are  produced 
from  healthy  animals  and  which  do  not  carry  danger  of  any  kind  to 
the  health  of  the  consumer. 

THE  NATURE  OF  TUBERCULOSIS. 

EFFECTS  UPON  THE  ORGANS  OF  THE  BODY. 

The  most  striking  feature  about  the  disease  known  as  tuberculosis  is 
the  formation  in  different  parts  of  the  animal  body,  but  particularly  in 
the  lymphatic  glands,  the  lungs  and  liver,  of  small  masses  or  nodules, 
yellowish,  grayish,  or  whitish  in  color,  which  are  called  tubercles.  It 
is  from  this  characteristic  that  the  disease  receives  its  name.  Tuber- 
culosis is  therefore  that  diseased  condition  of  the  animal  body  in  which 
tubercles  are  formed.  There  are,  however,  other  diseased  conditions 
accompanied  by  the  formation  of  similar  nodules  which  ma}'  also  be 
called  tubercles,  and  therefore  it  would  be  necessary  in  formulating 
an  exact  definition  of  tuberculosis  to  specify  tubercles  caused  by  the 
Bacillus  tuberculosis.  We  might  therefore  say  that  tuberculosis  is  the 
disease  caused  by  the  Bacillus  tubwculosis  and  characterized  by  the 
formation  of  tubercles  in  various  parts  of  the  animal  body. 

It  was  formerly  believed  that  the  lungs  were  affected  in  nearly  every 
case  of  tuberculosis,  but  more  careful  studies  have  shown  that  the 
glands  of  the  neck  and  chest  are  even  more  frequently  affected  than 
the  lungs.  From  the  very  careful  autopsies  made  on  the  animals 
of  the  Soldiers'  Home,  Washington,  D.  C.,  in  1893  by  Dr.  Theobald 
Smith,23  at  that  time  pathologist  of  the  Bureau  of  Animal  Industry, 
the  following  interesting  information  as  to  the  parts  affected  was 
obtained: 

Total  number  of  animals  in  the  herd (50 

Total  number  of  animals  infected  (88  per  cent) 53 

Number  in  which  retropharyngeal  glands  only  were  affected 5 

Number  in  which  the  bronchial  glands  only  were  affected 5 

Number  in  which  the  mediastinal  glands  only  were  affected 5 

Number  in  which  the  thoracic  glands  but  not  the  lungs  were  diseased -7 

Number  in  which  lungs  were  affected 20 

Number  with  exclusively  thoracic  lesions 26 

Number  with  exclusively  abdominal  lesions 1 

Total  number  in  which  retropharyngeal  glands  were  affected 9 

Numbt-r  in  which  disease  of  the  thoracic  organs  was  detected 47 

Number  in  which  lungs  were  diseased  and  glands  healthy 1 

Number  in  which  digestive  tract,  including  head  glands,  was  affected 26 

Number  in  which  intestinal  walls  were  affected 1 

Number  in  which  mesenteric  glands  were  affected 16, 


Bulletin    No.  38,    B.  A.   I. 


P'ate   I. 


LUNGS  OF   A   HEALTHY   HOG. 


Plate 


UBERCULOUS  LUNGS  OF   HOG 


Bulletin    No.  38,   B.  A.  I. 


Plate 


OF    TUBERCULOUS   LUNGS   FROM   CATTLE 


Plate   IV, 


SPLEEN   Oh    HEALTHY   HOG. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS. 


17 


Number  in  which  portal  glands  were  affected 10 

Number  in  which  mesenteric  and  not  portal  glands  were  affected 10 

Number  in  which  portal  and  not  mesenteric  glands  were  affected 4 

Number  in  which  parenchyma  of  liver  was  involved 2 

Number  in  which  serous  membranes  were  affected 2 

Number  in  which  udder  glands  were  affected 1 

From  this  statement  the  following  table  showing  the  location  of  the 
disease  has  been  calculated  in  percentages: 


Organs  affected. 

Per  cent.1 

Organs  affected. 

Per  cent. 

Retropharyngeal  glands  only           . 

9.4 

Total  digestive  tract,  including  head 

Bronchial  glands  only  

9.4 

glands  

49.1 

9  4 

Intestinal  walls 

1  9 

Thoracic  glands  but  not  the  lungs 

50.9 

Mesenteric  glands 

30  2 

Lungs                                             

37.7 

Portal  glands  

18  8 

Lungs  but  not  the  thoracic  glands  

1.9 
49  1 

Mesenteric  and  not  portal  glands  
Portal  and  not  mesenteric  glands 

18.8 
7  5 

88.7 

Parenchyma  of  liver  

3.8 

Abdominal  organs  only               

1.9 

Serous  membranes  

3  8 

Total  retropharyneeal  glands  

17.0 

Glands  of  udder  

1.9 

This  table  shows  the  great  frequency  with  which  the  tubercular 
lesions  are  found  in  the  glands.  If  we  add  the  cases  in  which  the 
thoracic  glands  but  not  the  lungs  were  affected  (50.9  per  cent)  to  those 
in  which  the  retropharyngeal  glands  only  were  affected  (9,-i  per  cent), 
we  find  that  (50  per  cent  of  the  cases  had  these  glands,  and  not  the  lungs, 
affected.  It  is  veiy  seldom  that  the  lungs  are  affected  without  the 
thoracic  glands  being  also  diseased. 

Doctor  Pearson  2  has  given  the  result  of  1,200  post-mortem  exami- 
nations made  under  his  direction  for  the  State  live  stock  sanitary 
board  of  Pennsylvania.  The  following  is  a  tabular  statement  of  these 
observations,  the  organs  mentioned  being  arranged  in  the  order  of 
frequency  of  infection.  Practically  all  of  the  animals  covered  by  this 

table  were  milch  cows. 

i 

Distribution  of  lexioiis  in  1,200  cases  of  tuberculosis. 


Organs  affected. 

Number 
of  cases 
in  which 
affected. 

Per  cent 
of  cases 
in  which 
affected. 

Mediastinal  lymphatic  glands  

725 

60.42 

Right  lung...*  

724 

60.  33 

Left  lung  

685 

57.08 

Bronchial  lymphatic  glands  

404 

33.67 

Small  intestine  

388 

32.33 

Mesenteric  lymphatic  glands  .                        ...                      . 

278 

23.17 

Pleura  ^  

264 

22.00 

Liver  

247 

20.58 

Large  intestine  ...                                

189 

15.75 

Postpharyngeal  lymphatic  glands  

181 

15.  08 

Peritoneum  .                               

168 

14.00 

Lymphatic  glands  of  udder  

161 

13.42 

Diaphragm  ..             ...                                                      

136 

11.33 

Portal  lymphatic  glands  

123 

10.25 

Lymphatic  glands  of  flank                                   .                         .                 .             .... 

108 

9.00 

Udder  

104 

8.67 

Pericardium 

98 

8.17 

Lymphatic  glands  of  shoulder             

93 

7.75 

Stomach  

86 

7.17 

Spleen 

68 

5.67 

Uterus.             .     .        

66 

5.50 

Kidneys  

25 

2.  as 

1  SSI— No.  3X— 0(5- 


18  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

Of  course  in  a  great  many  of  these  cases  lesions  were  found  in  a 
number  of  organs,  and  sometimes  they  were  distributed  throughout 
the  abdominal  and  thoracic  cavities.  No  reference  is  made  to  lesions 
in  the  brain,  skin,  muscles,  bones,  or  joints,  because  these  parts  were 
not  examined  in  all  cases. 

Wherever  the  disease  is  located,  it  is  usually  made  manifest  by  the 
formation  of  a  number  of  tubercles  the  size  of  a  pin  head  or  smaller. 
If  the  tubercles  are  numerous  and  situated  near  to  each  other,  they 
may  become  joined  together  in  varying  numbers,  forming  tubercular 
masses.  Both  the  individual  tubercles  and  the  tubercular  masses 
undergo  certain  changes  by  which  they  may  become  soft,  cheesy,  or 
semiliquid,  and  in  other  cases  they  may  become  gritty  or  hard  through 
the  depositing  of  lime  salts.  By  such  changes  a  lymphatic  gland  may 
be  greatly  enlarged  and  filled  with  tubercular  material,  which,  when 
cut  across,  is  found  to  be  calcified  and  hard  or  broken  down  and  soft- 
ened until  it  has  acquired  a  cheesy  or  pasty  consistency. 

The  tubercles  which  form  in  the  lungs  go  through  changes  similar 
to  those  just  described  as  occurring  in  the  glands,  but,  owing  to  the 
different  structure  of  these  organs,  there  are  complicating  changes  in 
the  lungs  which  give  the  lesions  a  somewhat  different  appearance. 
The  irritation  caused  by  the  tubercles  usually  leads  to  the  development 
of  bronchitis  with  an  abundant  catarrhal  secretion  which  fills  the 
smaller  air  tubes,  shuts  off  the  air  supply,  causes  the  collapse  of  the 
lung  tissue  thus  deprived  of  air,  and  leads  to  the  depositing  of  yellow- 
ish cheesy  matter  in  the  air  tubes  and  cells  of  this  portion  of  the  lung. 
This  condition  is  known  as  tubercular  broncho-pneumonia. 

In  Plate  I  the  lungs  of  a  healthy  hog  are  shown  in  order  to  enable  the 
reader  to  compare  these  with  the  illustrations  of  tuberculous  lungs. 
The  color  is  uniform  except  for  light  and  shade,  the  surface  is  smooth, 
and  the  tissue  is  spongy  and  elastic.  The  normal  lungs  of  other  kinds 
of  animals  have  a  similar  appearance.  The  tuberculous  lungs  of  a  hog 
are  represented  in  Plate  II.  Innumerable  small  tubercles  are  seen 
almost  covering  the  surface,  and  many  lobules  are  collapsed  and  of  a 
deep  red  color.  Toward  the  upper  portion  of  the  illustration,  between 
the  lungs,  the  enlarged  and  tuberculous  bronchial  glands  may  be  dis- 
tinguished. These  lungs  were  very  severely  affected,  but  the  tubercles 
have  for  the  most  part  remained  isolated — that  is,  they  have  not  united 
and  formed  the  tubercular  masses  which  are  sometimes  seen. 

Plate  III  shows  different  kinds  of  tubercular  lesions  observed  in  the 
lungs  of  cattle.  In  the  lower  figure  there  are  small  tubercular  masses 
distributed  throughout  a  limited  portion  of  one  of  the  lungs.  The 
middle  figure  shows  an  aggregation  or  union  of  such  masses,  through 
which  process  a  mass  of  considerable  size  has  been  formed,  and  around 
the  border  of  this  may  be  distinguished  a  white  fibrous  wall  which 
when  complete  enveloped  the  tubercular  material  and  shut  it  off  from 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  19 

the  tissue  of  the  lungs.  The  upper  figure  represents  a  tubercular  mass 
similar  to  that  just  described,  but  older.  The  fibrous  wall  surrounding 
it  is  more  distinct  and  thicker,  while  the  contents  are  more  broken 
down  and  homogeneous. 

When  a  large  number  of  tubercles  develop  on  the  surface  of  the 
lungs,  an  inflammation  of  the  pleura  may  be  caused,  with  the  forma- 
tion of  much  new  tissue  and  the  adhesion  of  the  lungs  to  the  ribs  or 
the  diaphragm.  Sometimes  the  disease  has  a  peculiar  tendency  to  the 
development  of  tubercular  growth  upon  the  pleura  and  other  serous 
membranes.  The  tubercular  masses  bud  and  branch,  thus  forming 
large  wartlike  growths;  or  groups  of  nodules  may  even  hang  from  the 
surface  suspended  by  delicate  threads  or  fibers  giving  the  appearance 
of  a  bunch  of  grapes.  These  collections  of  tubercles  have  often  been 
called  grapes,  and  this  form  of  the  disease  is  known  as  "pearly  dis- 
ease," on  account  of  the  pearly  color  and  glistening  appearance  of  the 
serous  membrane  covering  the  projecting  buds  and  spherical  masses. 
In  many  cases  both  the  lungs  and  serous  membranes  are  affected,  but 
often  there  are  extensive  growths  of  this  kind  upon  the  surface  of 
the  lung,  while,  singularly  enough,  the  tissue  of  the  lung  remains 
unattacked. 

With  extensive  tubercular  disease  of  the  lungs  and  pleura  the 
bronchial  and  mediastinal  lymphatic  glands  generally  become  loaded 
with  tubercular  deposit  and  enormously  enlarged.  In  some  instances 
they  constitute  masses  of  tubercular  material  mam'  pounds  in  weight. 

The  organs  in  the  abdominal  cavity  are  also  frequently  the  seat  of 
tubercular  disease.  In  the  herd  of  the  Soldiers'  Home,  above  referred 
to,  more  than  40  per  cent  of  the  animals  had  abdominal  lesions.  The 
mesenteric  and  portal  glands  are  the  organs  most  commonly  affected, 
but  tubercles  are  often  found  in  other  lymphatic  glands  of  this  region, 
and  also  in  the  liver,  spleen,  kidneys,  ovaries,  uterus,  and  even  in  the 
intestinal  walls. 

In  Plate  IV  the  figure  to  the  right  illustrates  the  appearance  of  the 
normal  spleen  of  a  hog.  Its  uniform  color  and  regular  outline  should 
be  noted.'  The  figure  to  the  left  represents  the  tubercular  spleen  of 
a  hog.  Observe  here  the  yellowish  masses  of  tubercular  material 
which  cause  elevations  of  the  surface,  and  the  color  of  which  may  be 
plainly  distinguished  through  the  membrane  which  covers  the  organ. 

Plate  V  was  made  from  a  case  of  tuberculosis  of  the  liver  of  a  cow. 
A  large  portion  of  the  lobe  of  the  liver  which  is  shown  in  the  plate 
has  undergone  tuberculous  changes  and  been  converted  into  a  solid 
mass  of  tubercular  material.  The  nodules  seen  in  this  illustration  are 
in  various  stagesof  the  disease,  but  the  majority  contain  the  yellowish, 
partly  cheesy,  partly  gritty  substance  which  is  characteristic  of 
advanced  tuberculous  degeneration. 

Plate  VI  is  an  illustration  made  from  a  case  of  severe  tuberculous 


20  TUBERCULOSIS    OF    THE    FOOD-PRODUOTNG    ANIMALS. 

pericarditis  of  a  cow.  The  pericardium  or  sac  .surrounding  the  heart 
is  seen  greatly  thickened  by  the  formation  of  tubercular  material,  and 
the  heart  itself  is  compressed  and  misshapen. 

In  Plate  VII  the  lower  figure  represents  the  tuberculous  ovaries  of  a 
cow.  Many  nodules  of  a  size  approximating  that  of  a  pin  head  are 
visible  over  the  surface  of  the  organ,  and  some  are  deeply  buried  in 
its  substance.  The  upper  figure  was  drawn  from  a  portion  of  a  child's 
intestine  which  was  thickly  covered  with  small  tubercles.  The  great 
development  of  the  tubercular  process  in  this  case  is  readily  appre- 
ciated from  the  appearance  of  the  plate.  This  class  of  cases  has  been 
attributed  to  infection  taken  into  the  stomach,  and  some  of  these  cases 
are  supposed  to  be  due  to  infected  cow's  milk. 

The  udder  of  cows  is  sometimes  attacked  by  tuberculosis,  in  which 
case  one  of  the  quarters  is  found  to  be  swollen,  uniformly  firm  or 
hard,  and  painless.  In  rare  cases  one-half  of  the  udder  may  be 
affected.  Tubercles  are  formed  throughout  the  affected  part  of  the 
organ,  and  there  may  be  tubercles  and  tuberculous  ulcerations  upon  the 
surface  of  the  membranes  lining  the  milk  tubes.  When  such  a  condi- 
tion is  established  the  milk  becomes  thin  and  watery  and  contains  innu- 
merable tubercle  bacilli.  As  the  disease  progresses  larger  nodules, 
such  as  have  been  described  in  other  organs,  form  within  the  udder 
and  undergo  degeneration,  softening,  and  liquefaction.  If  such  a 
tuberculous  mass  opens  into  a  milk  duct,  as  is  often  the  case,  the 
liquid  or  semiliquid  contents  become  mixed  with  the  milk. 

Plate  VIII  is  an  illustration  of  a  tuberculous  udder  which  has  been  cut 
across  to  show  the  distribution  of  the  tuberculous  material.  This  part 
of  the  organ  is  filled  and  distended  with  the  tuberculous  deposits,  and 
the  milk  cistern  showing  near  the  lower  portion  is  ulcerated,  lined 
with  tubercles,  and  covered  with  cheesy  particles.  At  the  upper 
portion  of  the  illustration  may  he  seen  the  supramammary  lymphatic 
gland,  which  is  greatly  enlarged  and  studded  with  small  tubercles. 

Tubercles  are  often  found  in  the  lymphatic  glands  in  front  of  the 
shoulder  and  in  the  flank,  and  in  those  embedded  in  various  parts  of 
the  muscular  tissue.  As  such  glands  are  situated  in  the  portions  of 
the  carcass  used  for  food,  it  is  important  that  they  should  be  examined 
before  the  carcass  of  a  tuberculous  animal  is  utilized  for  this  purpose. 
A  tuberculous  lymph  gland  is  shown  in  Plate  IX. 

The  bones  may  also  be  invaded  by  the  tubercular  process,  especially 
in  swine,  and  sometimes  the  whole  interior  of  one  or  more  bones  will 
be  filled  with  tubercular  material,  either  just  developed  or  undergoing 
degeneration.  Often  the  joints  are  affected,  causing  swelling,  inflam- 
mation, and  lameness.  The  brain  and  spinal  cord  are  by  no  means 
exempt  from  tuberculous  disease,  but  owing  to  thedifh'cult}7  of  remov- 
ing these  organs  for  examination  we  have  fewer  statistics  relative  to 
them  than  to  most  other  parts  of  the  body.  Semmer  found  tubercu- 


Bulletin   No.  38,  B.  A.  I. 


Plate  V. 


TUBERCULOUS    LIVER  OF  COW. 


Bulletin   No.  38,  B.  A.  ». 


Plate  VI. 


TUBERCULOUS   PERICARDITIS  OF   COW. 


Bulletin  No.  38,  B.  A.  I. 


Plate  VII. 


TUBERCULOUS  INTESTINE  OF  A  CHILD. 


TUBERCULOUS  OVARY  OF  COW. 


Bulletin   No,  38,  B.  A.  I. 


Plate  VIII. 


TUBERCULOUS   UDDER  OF  COW. 


Bulletin  No.  38,  B.  A.  I. 


Plate  IX. 


Haines  del.  1904. 


TUBERCULOUS    LYMPHATIC    GLAND    OF    COW. 


MATERIAL    FAOTS    CONCERNING    TUBERCITLOSIS.  21 

losis  of  the  brain  in  4  out  of  40  cases  examined.  The  tubercles  are 
located  on  the  membranes  of  the  brain  and  spinal  cord,  and  are  also 
found  scattered  through  the  interior  tissue  of  these  organs. 

It  will  be  seen  from  what  lias  preceded  that  tuberculous  disease  may 
be  found  in  any  part  of  the  animal  body,  and  that  while  there  are 
certain  organs  which  are  affected  more  frequently  than  others,  none 
of  the  living  tissues  is  altogether  exempt  from  its  invasion. 

The  generalized  form  of  tuberculosis  is  that  in  which  the  infection 
gets  into  the  blood  and  is  distributed  through  the  circulation  to  man}' 
parts  of  the  body.  Slaughterhouse  statistics  of  different  countries  of 
Europe  indicate  that  about  9  or  10  per  cent  of  the  cases  of  tubercu- 
losis in  cattle  are  in  this  form.  Rieck,  quoted  by  Ostertag,  states,  as 
a  result  of  the  careful  examination  of  430  cases  of  generalized  tuber- 
culosis in  the  abattoirs  of  Leipzig  from  1880  to  1891,  that  the  follow- 
ing percentages  indicate  the  proportion  of  these  cases  in  which  the 
different  organs  of  the  carcasses  were  affected: 


Organs.  |  Per  cent.  Organs 


Per  cent. 


Lungs 100.0   ;  Muscles    and    intermuscular    lymph 

Liver 83.0!      glands 49.3 

Intestinal  canal !          73.0      Spleen 18.6 

Serous  membranes 57. 4   !  Udder 16.  7 

Kidnevs  ..  52.5   |  Bones  ..  8.8 


SYMPTOMS. 

In  the  great  majority  of  cases  of  tuberculosis  in  animals  the  symp- 
toms are  slight  and  not  at  all  clear  in  their  indications.  As  the  func- 
tions of  the  body  must  be  disturbed  more  or  less  before  any  svmptoms 
are  apparent,  it  is  plain  that  in  the  earliest  stages  of  the  disease  there 
are*  no  symptoms,  and  that  when  symptoms  develop  the  disease  is 
already  considerably  advanced.  .It  is  only  when  the  affected  part  is 
located  where  it  may  be  easily  examined  that  symptoms  are  shown  by 
which  the  infection  may  be  detected  at  a  comparatively  early  stage. 
Thus  when  the  udder  or  the  glands  of  the  neck  are  the  seat  of  tuber- 
culosis the  existence  of  the  trouble  is  more  likely  to  be  revealed  than 
when  the  affected  organ  is  within  one  of  the  body  cavities. 

If  the  larynx,  the  air  tubes,  or  the  lungs  are  affected  there  is  a  short 
cough,  which  is  heard  particularly  in  the  morning  at  feeding  time  or 
when  the  animal  is  let  out  of  the  stable  in  the  cold  air,  or  after  it  has 
been  drinking  cold  water,  and  especially  after  violent  exertion.  This 
cough  generally  becomes  more  prolonged  and  convulsive  as  the  disease 
advances. 

In  case  the  uterus  or  ovaries  are  effected  there  ma}-  be  abortion  or 
sterility  with  abnormal  sexual  manifestations.  If  the  intestines  are 
affected  there  may  be  irregular  attacks  of  diarrhea.  If  a  joint  is  dis- 
eased it  is  revealed  by  lameness. 

As  the  disease  progresses  the  general  health  of  the  animal  and  the 


22  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

functions  of  nutrition  arc  affected.  Animals  which  have  been  in  good 
flesh  and  laying  on  fat  fail  to  profit  by  their  food  and  begin  to  l<»s<> 
flesh;  there  is  a  lusterless,  staring,  rough  coat  of  hair,  the  skin 
becomes  tense,  the  bones  prominent,  and  the  eyes  sunken  in  their 
sockets.  The  milk  secretion  diminishes  and  the  milk  becomes  thin, 
watery,  and  blue.  In  case  the  serous  membranes  of  the  chest  become 
irritated  by  the  tubercular  deposits,  pressure  applied  over  the  ribs 
may  cause  the  diseased  animal  to  cough,  moan,  seek  to  escape,  and 
otherwise  manifest  evidence  of  tenderness  in  this  region. 

The  ear  applied  to  the  walls  of  the  chest  may  sometimes  detect 
abnormal  sounds,  such  as  loud  crepitation,  gurgling,  whistling,  and 
creaking,  or  there  may  be  areas  where  the  respiratory  murmur  is 
entirely  lost.  Percussion  sometimes  shows  abnormal  resonance  and 
sometimes  areas  of  dullness  corresponding  to  tubercular  deposits  or 
adhesions  of  the  lungs  to  the  chest  wall. 

In  most  animals  there  is  high  temperature,  progressive  emaciation, 
and  loss  of  strength  until  death  results.  With  some  cases  the  general 
nutrition  of  the  body  remains  unaffected  and  these  symptoms  of  the 
final  stages  of  the  disease  are  postponed  until  after  the  lungs  or  other 
vital  organs  have  been  almost  completely  filled  with  tubercular  deposit. 
But  if  the  disease  continues  to  make  progress  there  must  come  a  time 
when  the  nutrition  and  vigor  fail  to  maintain  themselves  and  rapid 
prostration  follows.  There  are  cases,  however,  with  animals  as  with 
men,  in  which  the  forces  of  the  body  triumph  over  the  disease,  and 
the  progress  of  the  tubercular  formation  is  arrested.  The  tubercular 
material  is  then  inclosed  by  fibrous  walls  which  shut  it  off  from  the 
living  tissues  of  the  body,  caseation  and  softening  or  calcification 
take  place,  and  in  the  course  of  time  the  bacilli  may  die  and  di^ip- 
pear.  Unfortunately,  these  cases  are  the  exception  and  not  the  rule. 

In  those  cases  which  progress  to  a  fatal  end  the  attitude  and  general 
appearance  of  cattle  are  quite  characteristic  during  the  final  stages. 
The  emaciation  is  extreme;  the  outlines  of  the  bones  are  clearly  visi- 
ble; the  skin  is  tightly  drawn  over  the  skeleton;  the  coat  is  rough 
and  without  luster;  the  animal  remains  almost  constantly  standing; 
the  nose  is  raised  and  the  head  extended  on  a  line  with  the  neck;  the 
elbows  are  turned  out  to  facilitate  the  expansion  of  the  chest;  the 
eyes  are  sunken,  and  there  is  a  haggard  expression  to  the  face  in 
harmony  with  the  general  appearance  of  the  body. 

The  symptoms  of  tuberculosis  in  hogs  are  very  obscure  and  difficult 
to  detect.  In  the  great  majority  of  cases  no  symptoms  are  noticed 
and  the  disease  is  only  recognized  by  an  examination  of  the  carcass. 
The  parts  most  frequently  affected  are  the  glands  of  the  neck,  the 
bronchial,  mediastinal,  mesenteric,  and  portal  glands,  the  liver,  lungs, 
kidneys,  and  spleen.  In  numerous  cases  the  glands  of  the  carcass  are 
affected,  and  tuberculosis  of  the  bones  and  joints  is  common. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  23 

Although  there  is  a  groat  tendenc}r  for  tuberculosis  to  spread  to 
different  parts  of  the  body  in  swine,  causing  it  to  become  more  fre- 
quently generalized  with  these  animals  than  with  cattle,  the  rapidity 
with  which  they  take  on  fat  apparently  enables  them  to  resist  the 
destructive  influence  of  the  disease,  at  least  to  the  age  at  which  they 
are  generally  slaughtered.  Animals  which  come  to  market  fat  and 
appear  perfectly  well  just  before  slaughter  may  be  found  quite 
seriously  diseased. 

In  some  cases,  however,  swine  may  show  enlargement  of  the  glands 
of  the  neck  and  of  other  parts  of  the  bod}',  diarrhea,  emaciation,  and 
tubercular  inflammation  and  swelling  of  one  or  more  joints.  When 
the  nutrition  of  the  body  is  affected,  as  shown  by  loss  of  flesh,  the 
disease  usually  runs  a  rapid  course  and  causes  the  death  of  the  animal 
in  a  few  weeks. 

EFFECTS    UPON    A    HERD   OF   CATTLE. 

It  is  no  less  important  to  study  the  effects  of  tuberculosis  upon  a 
herd  of  cattle  than  to  study  its  effect  upon  the  individual  animal.  The 
experience  of  those  who  have  had  herds  free  from  the  disease  but  who 
have  had  the  misfortune  to  introduce  it  and  have  seen  it  develop  among 
their  animals  must  be  of  the  greatest  value  to  others  who  desire  to 
guard  against  it.  A  number  of  such  cases  have  been  carefully  studied 
at  the  experiment  stations  and  elsewhere  and  the  principal  features  of 
the  outbreaks  ascertained. 

AX    EXPERIMENT    WITH    TrBERCfLOUS   CATTLE. 

Phelps2*  relates  experiments  with  four  condemned  cows  which  were 
placed  by  the  Connecticut  State  cattle  commission  at  the  disposal  of 
the  Storrs  Experiment  Station  for  the  purpose  of  making  some  obser- 
vations and  experiments  on  bovine  tuberculosis.  The  herd  from 
which  these  animals  came  had  been  officially  tested  in  March,  1896, 
and  several  animals  in  the  herd  were  condemned  and  slaughtered, 
although  the  four  cows  mentioned  failed  to  respond  and  were  tagged 
as  free  from  the  disease.  In  October,  1896,  the  herd  was  tested  again 
by  the  commissioners,  and  these  four  cows  responded  and  were  then 
condemned  as  tuberculous.  Shortly  afterwards  they  were  brought  to 
the  station  and  were  kept  in  quarantine  until  they  were  slaughtered  in 
the  fall  of  1900. 

These  particular  animals  were  chosen  for  the  experiment  because 
there  was  good  reason  to  believe  that  the  disease  was  present  in  its 
earlier  stages.  While  the  cows  were  at  the  station  they  were  kept 
isolated  from  other  cattle  in  a  high,  light,  and  airy  stable  with  about 
1,500  cubic  feet  of  air  space  per  cow,  although  later  several  calves 
which  were  used  in  the  experiments  with  the  cows  occupied  the  same 
stable.  Adjoining  the  stable  was  a  small  yard  about  one-half  acre  in 
area  in  which  the  animals  were  allowed  to  exercise  several  hours  each 


24  TUBERCULOSIS    OB1    THE    FOOD-PRODUCING    ANIMALS. 

day,  except  in  very  stormy  or  extremely  cold  weather.  No 
treatment  for  the  disease  was  attempted,  hut  good  care  and  feed  were 
afforded  at  all  times.  During  the  first  year  that  the  animals  were 
under  observation  all  four  cows  remained  in  good  condition  and  showed 
no  outward  sign  of  disease.  It  is  evident  that  these  cows  were  received 
at  the  station  soon  after  their  infection,  when  the  disease  had  made 
but  slight  progress  and  before  the  general  health  of  the  animals  was 
noticeably  affected.  They  were  kept  under  excellent  sanitary  condi- 
tions, with  outdoor  exercise  and  good  food,  and  were  protected  from 
the  worst  weather.  They  should,  therefore,  have  done  much  better 
than  the  average  farm  cow  after  it  is  infected  with  this  disease. 

The  history  of  these  cows  at  the  station  is  very  instructive,  and  is. 
in  brief,  as  follows: 

Cow  No.  1337.  This  cow  produced  a  vigorous  calf  April  5,  1897.  The  calf  suckled 
its  dam  for  six  months,  and  was  then  placed  in  the  college  herd.  During  1898  the 
cow  appeared  to  be  in  vigorous  health  and  remained  in  good  condition  of  flesh.  She 
dropped  a  well-developed  calf  in  September,  1898,  which  was  allowed  to  suckle  its 
dam  for  about  a  year.  During  1899  she  remained  in  a  vigorous  state  of  health,  and 
produced  a  healthy  calf  in  December,  1899.  Although  this  calf  appeared  vigorous 
and  strong  at  birth,  it  was  soon  after  attacked  by  scours  and  died  in  a  few  days. 
During  1900  the  cow  remained  in  good  flesh,  had  a  sleek  coat,  and  continued  to  give 
a  good  flow  of  milk.  Early  in  the  year  she  developed  a  slight  cough,  but  otherwise 
appeared  in  perfect  health  when  killed  in  November,  1900.  Examination  of  the  car- 
cass showed  the  mediastinal  lymphatics  to  be  tuberculous,  and  a  tuberculous  nodule 
was  found  in  the  right  lung.  The  other  organs  were  normal. 

Cow  No.  1341.  This  cow  dropped  a  dead  calf  in  March,  1897,  the  carcass  of  which 
was  carefully  examined,  but  revealed  no  signs  of  tuberculosis.  She  produced  a  well- 
developed  calf  in  August,  1898,  and  seemed  to  be  in  a  good  state  of  health  through- 
out the  following  winter.  During  1899  she  remained  in  fair  flesh  and  gave  a  good 
flow  of  milk  until  July.  At  that  time,  while  being  fed  green  oats  and  peas,  she  was 
attacked  by  scours  and  began  to  run  down  rapidly.  She  ceased  giving  milk  for  a 
short  time,  but  when  placed  on  dry  feed  began  to  regain  flesh  and  milk  flow.  She 
remained  in  a  fair  state  of  health  during  the  fall,  but  had  a  tendency  to  looseness  of 
the  bowels.  A  healthy  calf  was  produced  in  February,  1900,  which  was  followed  by 
a  good  flow  of  milk  for  several  months,  but  during  the  spring  and  summer  she  lost 
flesh  rapidly  until  her  flanks  were  hollow  and  her  ribs  protruded  plainly.  The  coat 
became  rough,  the  eyes  dull  and  sunken,  the  cough  increased,  and  the  breathing 
became  more  frequent.  This  cow  continued  to  scour  intermittently,  and  when  killed 
in  November,  1900,  was  generally  emaciated,  although  continuing  to  give  milk  up  to 
the  time  of  her  slaughter.  Two-thirds  of  the  right  lung  and  one-half  of  the  left  lung 
were  filled  with  tuberculous  tissues  and  the  mediastinal  lymphatics  were  diseased. 

Cow  No.  1343.  This  animal  became  quite  fat  during  the  early  part  of  1898.  She 
dropped  a  rather  small  calf  in  August,  1898,  and  was  considerably  thinner  than  usual 
for  three  months  after  calving,  but  soon  after  that  began  to  gain  in  flesh.  Later  in 
the  fall  it  was  noticed  that  she  had  a  persistent  cough.  During  the  spring  and  sum- 
mer of  1899  she  continued  to  give  a  fair  flow  of  milk,  but  was  not  as  fat  as  in  1898. 
Her  cough  increased  during  the  winter  of  1898-99,  and  in  the  following  spring  it  was 
noticed  that  she  coughed  badly  after  eating  dry  feed  or  when  made  to  exercise  vig- 
orously. However,  she  produced  a  vigorous  calf  in  December,  1899,  but  this  was 
soon  after  attacked  by  a  mild  form  of  scours,  from  which  it  recovered.  She  gave  a 
fair  flow  of  milk  during  the  early  part  of  the  year  1900,  although  she  was  losing  flesh 
and  had  an  increasing  cough  and  short,  hurried  breathing.  During  the  fall  of  1900 
she  lost  flesh  rapidly,  had  a  rough  coat,  sunken  eyes,  and  protruding  ribs.  She  lost 
her  appetite,  and  in  October  ceased  to  give  milk,  and  when  slaughtered  in  November 
was  very  much  emaciated.  Up  to  within  a  year  of  the  time  of  slaughtering,  this  cow 
had  been  the  fattest  and  sleekest  of  the  four.  The  examination  of  the  carcass  showed 
both  lungs  badly  diseased,  almost  solidified  with  tuberculous  tissue,  the  chest  walls 
covered  with  tubercles,  and  the  mediastinal  and  mesenteric  lymphatics  badly  tuber- 
culous. Tubercles  were  found  on  the  rumen  and  the  diaphragm. 

Cow  No.  1344.  This  cow  remained  farrow  during  1898,  but  continued  to  give  a 
good  flow  of  milk.  During  the  fall  of  1898  she  gained  in  flesh  and  appeared  to  be  in 


MATERIAL    FACTS    OONTERNTNO    TUBERCULOSIS. 


a  healthy  and  vigorous  condition.  She  remained  in  this  condition  until  some  time 
in  the  summer  of  1899,  when  she  showed  lameness  in  the  right  stifle  joint.  She 
calved  in  October,  1899,  but  the  calf  was  weak  at  birth,  and  refused  to  eat.  It  died 
about  a  week  after  birth.  The  cow  gave  a  good  flow  of  milk  for  several  months  after 
calving,  but  was  thinner  than  usual.  During  the  early  part  of  1900  she  lost  flesh 
rapidly,  though  still  giving  a  good  flow  of  milk.  She  also  developed  a  severe  cough, 
which'  was  especially  noticeable  when  she  was  made  to  exercise  vigorously.  The 
lameness  in  the  stifle  joint  increased  in  severity  and  became  very  troublesome  to  the 
cow.  She  lost  flesh  during  the  summer  and  fall,  and,  although  not  as  emaciated  as 
Nog.  1341  and  1342,  was  quite  thin,  had  a  rough  coat,  and  appeared  to  be  in  a  bad 
physical  condition  when  slaughtered  in  November,  1900.  The  examination  of  the 
carcass  showed  the  mediastinal  lymphatics  diseased  and  an  abscess  in  the  left  lung. 

With  three  of  the  four  cows  in  this  experiment  the  disease  pro- 
gressed from  the  very  earliest  stage  to  a  point  where  the  animals  were 
worthless  within  about  four  years.  With  the  fourth  animal  it 
remained  nearly  stationary  and  did  not  apparent!}'  affect  the  general 
health. 

SPREAD    OP   TUBERCULOSIS    BY    DISPERSION    SALE. 

Russell25  gives  the  following  example  of  the  dissemination  of  a  dis- 
eased herd: 

In  October,  1903,  a  public  sale  was  held  in  one  of  the  southern  counties  of  Wiscon- 
sin, at  which  a  herd  of  46  head  of  cattle  were  disposed  of  in  order  to  divide  up  the 
interest  of  the  landlord  and  the  tenant.  These  46  head  were  purchased  by  twelve 
persons.  The  landlord,  wishing  to  retain  what  he  thought  were  the  most  valuable 
animals,  bad  a  friend  buy  in  for  him  18  head,  while  the  tenant  bought  3  for  himself. 

One  of  the  parties  who  had  purchased  6  of  these  animals  decided  in  the  following 
February  to  have  his  herd  tested  for  tuberculosis.  A  neighbor,  hearing  that  the  test 
was  to  be  applied,  asked  to  have  his  family  cow  tested  at  the  same  time.  The  result 
of  the  test  was  to  show  positive  reactions  in  the  case  of  this  single  animal  and  also 
in  3  out  of  the  lot  of  6  which  had  been  purchased.  This  revelation  led  the  original 
owner  to  investigate  the  condition  of  the  portion  of  the  herd  which  he  had  pur- 
chased, and  in  this  case  14  of  the  original  18  were  found  to  be  affected. 

The  matter  at  this  stage  was  brought  to  the  attention  of  the  State.live  stock  sani- 
tary board,  and  after  a  lapse  of  some  weeks,  so  as  to  secure  normal  results,  retests  of 
these  herds  were  made.  In  addition,  all  the  herds  were  tested  into  which  any  animal 
had  been  introduced  from  the  herd  dispersed  at  the  sale.  The  results  of  these  tests 
are  shown  in  the  following  table: 

Dissemination  of  tuberculosis  into  various  herds  by  sale  of  slock. 


Herd. 

Number  of 
animals  in 
herd. 

Number  of 
animals 
from  origi- 
nal herd. 

Number  of 
tuberculin 
reactions. 

Number  of 
reactions 
in  animals 
purchased. 

1  .. 

21 

5 

3 

3 

•» 

18 

18 

14 

14 

3  

38 

6 

3 

3 

4 

8 

3 

2 

5  ...            

5 

2 

•> 

1 

C  

3 

3 

3 

3 

1 

1 

1 

j 

8  ...                

15 

1 

I 

9  

32 

1 

1 

1 

10  

18 

3 

0 

0 

11  

2 

1 

1 

1 

12  

2 

2 

13  

22 

9 

1 

1 

It  is  evident  from  the  above  data  that  the  originally  affected  herd 
was  badly  diseased,  as  33  out  of  the  total  number  of  55  disposed  of  at 
the  sale  or  before  responded  to  the  tuberculin  test.  And  }-et  none  of 
these  animals  showed  any  appearance  of  the  disease,  and  no  one  ques- 
tioned their  healthy  condition  at  the  time  of  purchase.  The  fact  that 


2ti  TUBERCULOSIS    OF    THK    FOOD-PRODUCING    ANIMALS. 

the  owners  bought  in  a  large  portion  of  the  herd  is  evidence  that  they 
had  no  idea  of  the  existence  of  this  serious  disease. 

It  was  exceedingly  fortunate  that  the  first  test  happened  to  be  made 
so  soon  after  the  sale  of  this  herd,  as  the  disease  had  apparently  just 
begun  to  spread  in  the  herds  to  which  the  animals  from  it  were  taken. 
It  is,  nevertheless,  a  good  example  of  the  extent  to  which  the  infection 
may  be  disseminated  by  the  sale  of  animals  from  a  single  herd  which 
is  apparently  in  healthy  condition. 

HISTORIES   OF    AFFECTED    HERDS. 

The  following  history  of  the  introduction  and  development  of  the 
disease  in  the  herd  of  the  Connecticut  Agricultural  College  is  a  strik- 
ing example  of  the  danger  of  purchasing  cows  so  long  as  tuberculosis 
is  prevalent  in  dairy  herds:26 

Previous  to  1896  the  herd  consisted  of  grade  animals,  mostly  of  Jersey  and  Guernsey 
blood,  but  in  that  year  15  registered  Jerseys,  Guernseys,  and  Ayrshires  were  pur- 
chased. Since  then  the  acquisitions  to  the  herd  have  been  from  the  natural  increase 
of  these  animals,  and  the  occasional  purchase  of  grade  cows.  The  herd  was  exam- 
ined by  the  veterinarian  and  tested  with  tuberculin  in  1896.  The  registered  animals 
purchased  during  the  year  were  also  tested,  and  the  herd  was  pronounced  free  from 
tuberculosis.  The  tuberculin  test  was  applied  again  in  1897,  with  no  reactions. 

In  October,  1897,  several  grade  cows  were  purchased,  including  "  Fannie,"  a  grade 
Guernsey.  This  cow  was  bought  of  a  neighboring  farmer,  who  had  owned  and 
raised  her  from  a  calf.  Her  owner  reports  that  he  had  never  had  tuberculosis  in  his 
herd  and  had  never  used  the  tuberculin  test.  Fannie  was  a  smooth,  plump  cow, 
and  apparently  in  perfect  health.  When  purchased  she  was  tested  with  tuberculin, 
and,  as  she  did  not  respond,  was  given  a  permanent  place  in  the  herd.  She  remained 
apparently  in  good  health  until  about  November  1,  1898,  when  she  began  to  refuse 
a  portion  of  her  allowance  of  silage,  and  soon  after  commenced  to  scour,  but  at  no 
time  did  she  cough.  From  this  time  on  she  ran  down  rapidly,  and  was  killed  on 
November  20,  as  it  was  evident  that  she  could  live  but  a  day  or  two  longer.  A  post- 
mortem examination  showed  a  generalized  and  advanced  case  of  tuberculosis.  The 
herd  was  tested  with  tuberculin  December  28,  1898,  when  12  animals  responded;  it 
was  again  tested  May  22,  1899,  when  3  more  responded;  it  was  tested  for  the  third 
time  December  7,  1899,  when  2  more  responded;  and  it  was  tested  for  the  fourth 
time  April  16,  1900,  when  1  additional  animal  responded.  No  further  reactions 
occurred  in  subsequent  tests,  the  last  of  which  recorded  was  made  on  February  17, 
1902. 

Including  the  original  tuberculous  animal,  there  were,  consequently,  19  diseased 
animals  found  in  this  heard  of  49  animals,  the  disease  having  spread  to  that  extent 
in  about  two  and  one-half  years,  notwithstanding  that  it  was  discovered  at  the  end 
of  the  first  year,  and  that  affected  animals  were  removed  as  fast  as  they  were 
revealed  by  the  tuberculin  test. 

Russell3  gives  the  following  history  of  an  extensive  outbreak  of 
tuberculosis  among  cattle  which  recently  came  to  light  in  the  herd  of 
a  prominent  dairyman  supplying  milk  to  the  city  of  Beloit,  Wis. : 

The  owner  had  a  fine  dairy  farm  on  the  outskirts  of  the  city,  and  had  constructed 
ample  stable  room  to  accommodate  his  herd.  The  business  had  developed  until  at 
the  time  of  examination  70  animals  were  kept,  46  of  which  were  in  milk.  A  veter- 
inary examination  of  an  animal  somewhat  out  of  condition  revealed  the  presence  of 
tuberculosis,  much  to  the  surprise  of  the  owner,  and  the  tuberculin  test  was  then 
applied  to  the  whole  herd. 

Fifty-seven  in  this  herd  of  70  reacted  to  the  test.  Those  that  escaped  were  for  the 
most  part  young  stock.  Thirty-three  of  the  best  conditioned  of  the  57  reacting  ani- 
mals were  shipped  to  abattoirs  for  immediate  slaughter,  and  of  this  number  only  18 
passed  Federal  inspection.  Of  the  24  killed  on  the  farm  not  to  exceed  7  would  have 
passed  for  l>eef  had  they  been  sent  for  slaughter.  Thus  it  appears  that  32  of  the  57 
that  reacted  were  so  badly  affected  as  to  require  total  condemnation  of  the  carcasses. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  27 

The  owner  was  in  California,  but  it  was  admitted  by  the  herdsman  who  had 
handled  the  herd  in  previous  years  that  a  considerable  number  of  animals  had  died 
or  teen  killed  from  year  to  year  as  long  ago  as  1897.  Frequently  animals  had  been 
shot  to  get  rid  of  them  as  they  pined  away.  No  examination  was  made  and  the 
matter  was  allowed  to  drift  on  until  the  startling  revelation  was  made  by  the  use  of 
the  tuberculin  test.  The  slaughter  of  this  herd  revealed  many  cases  of  advanced 
tuberculosis,  and  in  some  instances  even  the  udders  were  found  diseased.  The  farm 
had  well-constructed  barns  and  stables,  which  were  kept  in  a  clean  and  sanitary 
manner,  but  no  provision  was  made  for  ventilation. 

Within  a  week  from  the  time  this  first-mentioned  herd  was  disposed  of,  another 
was  examined  in  the  southern  part  of  the  State  in  which  even  a  worse  condition  was 
found.  In  this  instance  the  herd  consisted  of  72  animals,  many  of  which  were  fresh 
in  milk,  as  the  product  was  to  supply  a  Swiss-cheese  factory.  The  condition  of  the 
stock  revealed  by  the  tuberculin  test  was  shocking.  Of  the  72  aniinals  tested,  69 
reacted.  Only  1  mature  animal,  a  yearling  bull,  and  a  young  calf  escaped  the 
disease. 

This  widespread  distribution  of  the  disease  was  found  to  be  due  to  the  usual  cause, 
neglect  and  failure  to  provide  proper  sanitary  surroundings.  For  several  years  the 
owner  had  been  losing  animals  from  time  to  time,  but  made  no  effort  to  learn  the 
cause  of  the  trouble.  This  last  winter  5  died,  the  year  before  2  others,  and  during 
previous  years  still  others.  Four  years  ago  he  sold  to  a  neighbor  5  head  of  young 
stock,  which  were  kept  on  pasture  during  the  summer.  In  the  fall  they  weighed 
less  than  when  bought,  and  were  condemned  when  shipped  to  Chicago.  Later  7  or 
8  others  were  bought  for  shipment,  3  of  which  were  condemned  when  inspected. 

The  post-mortem  findings  in  this  herd  revealed  many  cases  of  generalized  tuber- 
culosis, some  of  which  were  in  a  most  aggravated  form.  In  a  number  of  cases  the 
udders  showed  well-marked  physical  signs  of  disease.  The  development  of  the  dis- 
ease in  young  stock  in  both  lung  and  body  cavities,  with  the  infection  of  the  bowel 
itself,  bespoke  a  double  infection,  through  the  milk  as  well  as  through  the  air.  The 
stable  in  which  this  entire  herd  of  70  head  was  kept,  with  about  a  dozen  young 
calves,  was  located  in  a  stone  basement,  in  which  there  wras  absolutely  no  provision 
for  ventilation.  A  little  light  filtered  in  through  five  or  six  tightly  closed  sash  win- 
dows of  three  8  by  10  inch  panes  of  glass  to  each  window.  The  interior  of  the  stable 
was  so  dark  that  one  could  scarcely  see  to  read  ordinary  newspaper  print  unless  the 
doors  were  left  open.  In  addition  to  these  general  insanitary  surroundings,  the 
manure  on  the  floor  of  the  stable  was  over  a  foot  thick. 

The  way  these  two  herds  were  handled  is  markedly  contrasted  with  the  course  of 
action  that  was  pursued  in  the  following  case: 

A  few  weeks  ago  a  member  of  the  farmers'  course  at  the  Agricultural  College  wit- 
nessed a  demonstration  of  the  tuberculin  test,  and  while  he  had  no  reason  to  suspect 
the  presence  of  the  disease  in  his  own  herd,  he  went  home  with  the  thought  that  it 
would  be  prudent  for  him  to  apply  the  test  and  satisfy  himself  as  to  the  actual  con- 
dition of  his  animals.  In  his  herd  of  25  only  1  was  found  affected,  and  this  was  a 
registered  cow  that  had  been  bought  a  few  months  before  for  the  sum  of  $150.  This 
animal  was  the  only  recent  purchase  that  had  been  made. 

Recently  another  correspondent  wrote  that  he  applied  the  test  to  his  herd,  and 
found  that  3  out  of  5  registered  Holsteins  that  he  had  purchased  a  short  time  before 
at  an  expense  of  $1,500  were  affected. 

THE  CAUSE  OF  TUBERCULOSIS. 

THE    TUBERCLE    BACILLUS. 

Tuberculosis  is  caused  by  a  bacterial  organism  known  as  the  Bacilhis 
tuberculosis  microbe,  which,  so  far  as  is  known,  does  not  multiply  out- 
side of  the  animal  body  except  under  the  artificial  conditions  supplied 
in  laboratories.  As  we  find  the  bacillus  in  the  body  of  an  animal  it  is 
very  exacting  in  the  conditions  which  it  requires  for  its  growth,  and 
for  a  long  time  bacteriologists  found  it  difficult  to  make  it  develop  in 
their  laboratory  cultures.  Careful  study  of  its  peculiarities  has,  how- 
ever, resulted  in  the  discovery  of  methods  by  which  it  is  now  easily 
isolated  from  the  tissues  of  the  affected  animals  and  grown  in  pure 
cultures.  The  longer  it  is  grown  in  the  laboratory  the  more  readily 


28  TUBERCULOSIS    OF    THK    FOOD-PRODUCING    ANIMALS. 

it  is  cultivated,  as  it  adapts  itself  gradually  to  the  new  conditions;  but 
in  acquiring  this  exalted  power  to  live  and  multiply  outside  of  the 
animal  body  it  generally  loses  some  of  its  disease-producing  power 
and  becomes  less  and  less  virulent  until  in  the  course  of  time  it  may 
not  be  able  to  cause  disease  in  the  most  susceptible  animals. 

The  tubercle  bacillus  produces  tuberculosis  in  all  species  of  domesti- 
cated animals  and  probably  in  most  species  of  wild  animals,  though 
some  species  of  animals  are  very  much  more  susceptible  to  its  effects 
than  others.  It  is  able  to  multiply  in  the  bodies  of  birds  whose  tem- 
perature is  considerably  higher  than  that  of  mammals,  and  it  is  like- 
wise able  to  multiply  in  the  bodies  of  cold-blooded  animals  whose 
temperature  is  far  below  that  of  mammals.  It  therefore  lives,  propa- 
gates itself,  and  causes  disease  under  a  great  variety  of  conditions — a 
variety  which  is  truly  surprising  when  we  consider  the  delicacy  of  the 
germ  and  the  difficulties  which  were  encountered  in  cultivating  it  in 
the  laboratory. 

The  tubercle  bacillus  as  it  is  found  in  widely  different  species  of 
animals  is  not  always  identical  in  its  characteristics,  although  there  are 
certain  general  features  which  it  always  retains.  Its  peculiarities  in 
regard  to  staining  are  the  most  striking  of  these.  It  does  not  take  up 
the  usual  stains  which  are  successful  with  other  bacterial  organisms, 
and  consequently  must  be  stained  by  special  methods.  Koch  first  suc- 
ceeded in  coloring  it  by  leaving  it  for  several  hours  in  a  solution  of 
methylene  blue,  to  which  caustic  potash  had  been  added;  but  this 
method  wras  soon  superseded  by  a  solution  of  gentian  violet  in  water 
saturated  with  anilin  oil,  which  was  introduced  by  Ehrlich.  Of  late 
years  carbol-fuchsin  has  been  quite  generally  adopted  for  this  purpose. 
Another  peculiarity  of  the  tubercle  bacillus  is  that  having  once  taken 
a  stain,  it  fixes  it  very  firmly,  and  it  is,  therefore,  much  more  difficult 
to  decolorize  than  other  bacilli.  The  dilute  mineral  acids  will  remove 
these  colors  from  animal  substances  and  from  other  bacteria,  but  not 
from  the  tubercle  bacilli.  Advantage  is  taken  of  these  peculiarities  to 
make  microscopic  preparations  in  which  the  tubercle  bacilli  appear 
brightly  stained  while  everything  else  is  free  from  color,  or  to  make 
these  preparations  so  that  the  tubercle  bacilli  will  appear  red  and  all 
other  micro-organisms  will  be  blue. 

The  tubercle  bacillus  obtained  from  human  beings  is  able  to  grow 
between  the  temperature  limits  of  30°  and  40°  C. ;  that  obtained  from 
birds  is  able  to  grow  between  the  limits  of  25°  and  45°  0.;  while  a 
stock  of  tubercle  bacilli  obtained  by  Friedmann  from  a  tuberculous 
turtle  was  able  to  multipl}'  at  the  freezing  point  and  its  temperature 
limits  were  placed  by  the  discoverer  at  0°  to  43°  C.  The  bacilli  from 
these  different  sources  have  different  habits  of  growth  in  cultures,  and 
some  under  the  microscope  appear  longer,  thinner,  and  more  beaded 
than  others.  There  is  also  a  great  difference  in  the  virulence  of  the 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  29 

various  stocks  for  different  species  of  animals.  Human  bacilli  are  only 
with  difficulty  made  to  produce  disease  in  fowls  or  in  cold-blooded  ani- 
mals, and  the  greater  number  of  such  stocks  have  little  or  no  effect  upon 
bovine  animals.  Various  investigators  have  succeeded,  however,  in  mod- 
ifying the  different  stocks  of  bacilli,  and  have  been  able  to  infect  success- 
full}*  birds  and  cold-blooded  animals  with  human  and  bovine  bacilli, 
and  have  also  infected  mammals  with  the  tubercle  bacilli  of  birds. 

It  appears,  therefore,  that  the  tuberculosis  bacillus  is  one  which  is 
able  to  adapt  itself  to  a  wide  range  of  conditions,  and  that  the  bacillus 
as  found  in  the  tuberculous  lesions  of  birds,  mammals,  and  cold-blooded 
animals  is  the  same  organism  but  modified  somewhat  by  the  conditions 
of  environment. 

MANNER   OF    INFECTION    AND   DEVELOPMENT   OF   THE    DISEASE. 

The  tubercle  bacillus  may  enter  the  body  through  a  number  of  chan- 
nels and  thus  cause  infection.  With  cattle  it  is  most  f requently  drawn 
into  the  air  tubes  in  the  form  of  dust  floating  in  the  atmosphere  of  the 
stable.  In  many  cases,  however,  it  enters  into  the  alimentary  canal 
with  food  that  has  been  soiled  with  the  saliva  or  other  secretions  of 
diseased  animals.  It  may  also  gain  entrance  through  a  milk  duct  or 
through  the  vaginal  opening,  or  by  means  of  a  wound.  The  bacillus 
appears  to  be  able  to  penetrate  the  mucous  membranes,  at  least  in  cer- 
tain places,  even  when  there  is  no  wound  or  abrasion,  and  it  may  pass 
through  the  membrane  without  leaving  any  tubercular  material  or 
other  sign  to  show  where  it  gained  entrance.  However,  in  its  progress 
through  the  tissues  it  is  usually  soon  arrested  either  by  a  l\Tmphatic 
gland  or  in  some  other  manner,  and  then  it  multiplies  and  causes  the 
formation  of  a  tubercle.  The  channel  by  which  the  infection  occurred 
may  generally  be  determined  with  some  degree  of  certainty  by  the 
location  of  the  older  tubercles.  If  the  bronchial  or  mediastinal  glands 
show  the  earliest  lesions  the  infection  probably  came  through  the  in- 
spired air;  but  if  the  retropharyngeal,  mesenteric,  or  portal  glands 
have  the  oldest  lesions  the  infection  was  probably  through  contami- 
nated food. 

When  the  tubercle  bacilli  have  lodged  in  or  invaded  any  organ  their 
irritating  effect  upon  the  tissue  surrounding  them  sets  up  changes 
similar  to  those  seen  in  ordinary  inflammation.  The  fixed  connective 
tissue  cells  and  the  cells  of  the  endothelium  of  the  capillaries  begin  to 
multiply  and  produce  large  numbers  of  new  cells  which  group  them- 
selves side  by  side  in  the  form  of  a  hollow  sphere  around  the  bacilli. 
These  cells  are  then  called  epithelioid  cells,  and  for  the  reason  that  it 
is  composed  of  such  elements  the  tubercle  at  this  early  stage  is  known 
as  the  epithelioid  tubercle. 

After  the  tubercle  has  made  some  progress  in  its  development  by 
the  process  just  described  and  has  become  barely  visible  to  the  naked 


30  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

eye,  small  round  cells,  called  by  some  lymphoid  cells,  begin  to  gather 
around  the  sphere  of  cpithelioid  cells  and  may  become  so  numerous  as 
to  obscure  the  latter  and  cause  their  disappearance.  These  round  cells 
undoubtedly  come  from  the  blood  vessels  in  the  vicinity  which  have 
been  affected  by  the  adjacent  tuberculous  growth.  When  these  \ym- 
phoid  cells  have  increased  in  number  until  they  predominate  in  the 
newly  formed  tubercle,  this  is  called  a  lymphoid  tubercle. 

When  the  tubercle  develops  to  about  the  size  of  a  pin  head,  the 
lymphoid  cells  have  usually  become  so  numerous  that  they  interfere 
with  the  nutrition  of  the  central  portion,  and,  therefore,  the  cells 
located  at  the  center  begin  to  die.  As  the  cells  die  they  disintegrate, 
and  there  is  formed  a  granular,  caseous  material  from  which  the  bacilli 
have  disappeared.  When  this  process  occurs  slowly  it  is  accompanied 
by  the  formation  of  giant  cells,  that  is,  large  cells  containing  numer- 
ous nuclei.  These  cells  are  formed  either  by  the  fusion  of  a  number 
of  cells  together  or  by  an  abnormal  increase  in  the  protoplasm  of  a 
single  cell  together  with  the  multiplication  of  its  nuclei. 

As  the  tubercles  increase  in  size,  either  by  the  addition  of  more  cells 
or  by  the  fusion  of  two  or'  more  small  tubercles,  the  necrosed  and 
caseated  portion  at  the  center  becomes  larger,  and  as  this  process  con- 
tinues tubercular  masses  of  considerable  size  may  be  formed,  having 
the  same  general  appearance  as  the  smaller  tubercles,  but  with  a  rela- 
tively larger  proportion  of  caseous  material. 

When  the  center  has  undergone  partial  caseation,  the  epithelioid 
cells  surrounding  the  tubercle  may  be  gradually  changed  to  connective 
tissue  cells,  which  are  deposited  in  successive  layers  and  thus  form  a 
fibrous  wall.  By  the  time  the  former  cellular  elements  of  the  tubercle 
have  disappeared  this  fibrous  wall  or  capsule  becomes  firm  and  resist- 
ant and  completely  isolates  the  necrotic  focus. 

The  caseous  material  within  the  tubercular  mass  may  soften  and 
form  a  liquid  resembling  pus,  or  there  may  be  a  deposition  of  calcare- 
ous salts  which  at  first  form  as  small  angular  granules  and  later  co- 
alesce into  larger  nodules  until  finally  the  entire  caseous  material  may 
be  calcified.  This  change  is  very  common  with  both  cattle  and  hogs. 

After  an  animal  has  been  infected  with  tubercle  bacilli  and  the  first 
tubercle  has  commenced  to  develop  in  the  manner  above  described, 
more  or  less  bacilli  may  be  carried  from  this  first  point  of  infection 
with  the  streams  of  lymph  or  blood  and  lodge  elsewhere  to  cause  the 
formation  of  other  tubercles.  When  the  bacilli  are  carried  through 
the  lymph  channels  they  usually  arc  deposited  before  going  any  great 
distance,  and  hence,  in  this  case,  the  tubercles  are  limited  to  one  organ 
or  to  one  part  of  the  body;  but  if  the  bacilli  penetrate  the  blood  ves- 
sels in  great  numbers,  as  sometimes  occurs,  they  are  carried  to  all 
parts  of  the  body  and  generalized  tuberculosis  is  the  result. 

The  ways  in  which  tubercle  bacilli  escape  from  the  body  are  quite  as 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  31 

interesting  from  a  practical  point  of  view  as  the  ways  in  which  the}' 
enter  it.  There  are  a  number  of  channels  through  which  they  may 
be  disseminated,  but  the  most  common  ones  are  the  air  tubes,  the 
digestive  tube,  and  the  milk  ducts.  Tubercles  which  develop  near 
these  channels,  or  in  the  mucous  membrane  lining  them,  may  soften 
and  discharge  their  contents  into  the  tubes.  In  the  case  of  the  air 
tubes  the  material  is  coughed  up,  contaminates  the  saliva,  and  is  partly 
distributed  in  the  mangers  and  racks,  and  over  the  litter,  and  partly 
swallowed  to  pass  away  with  the  excrement.  In  the  case  of  tubercu- 
lar ulcers  on  the  internal  surface  of  the  intestine,  or  of  cavities  in  the 
lung  opening  into  the  bronchi,  or  of  similar  lesions  communicating 
with"  the  milk  ducts,  there  may  be  a  continuous  development  of  the 
bacilli  and  an  equally  continuous  discharge  of  vast  numbers  of  these 
germs  into  the  intestine,  the  bronchi,  or  the  milk  ducts,  as  the  case 
may  be.  An  animal  so  affected  is  most  dangerous  and  may  soon  infect 
most  of  the  individuals  in  the  herd.  The  bacilli  are  less  frequently 
distributed  from  the  genito-urinary  organs,  although  such  distribution 
may  occur  when  the  kidneys  or  uterus  are  the  seat  of  the  disease. 

On  the  other  hand,  the  tubercular  lesions  may  be  so  situated  that 
they  are  closed  in  and  have  no  channels  of  communication  with  the 
exterior,  as  in  those  cases  where  they  are  confined  to  a  bronchial, 
mediastinal,  or  mesenteric  lymphatic  gland.  Under  such  conditions 
an  affected  animal  may  remain  in  a  herd  for  a  long  time  without  com- 
municating the  disease  to  the  other  animals  of  the  herd.  But  prob- 
ably in  the  majority  of  such  cases  there  will  sooner  or  later  be  an 
extension  of  the  tubercular  formation  in  the  affected  animal,  when  it 
may  suddenly  and  without  warning  begin  distributing  the  bacilli  and 
infect  the  animals  which  are  stabled  or  pastured  with  it.  This  explains 
why  in  some  instances  a  tuberculous  cow  may  infect  the  greater  part  of 
a  large  herd  within  a  few  months,  while  in  other  instances  such  a  cow 
may  remain  in  a  herd  for  several  years  and  no  other  animals  become 
infected.  The  disease  is  of  the  same  nature  in  both  cases,  but  in  one 
case  the  bacilli  are  able  to  escape  from  the  body  of  the  diseased  animal, 
while  in  the  other  they  are  imprisoned  and  unable  to  do  further  harm. 

INFECTIVENESS   OF   MILK    OF   TUBERCULOUS   COWS. 

The  milk  of  tuberculous  cows  is  a  very  common  medium  for  carry- 
ing the  tubercle  bacillus  to  other  animals,  for  while  every  cow  affected 
with  the  disease  does  not  secrete  milk  contaminated  with  the  bacillus, 
there  are  frequently  one  or  more  cows  in  an  infected  herd  whose  milk 
is  infected,  and  this,  in  turn,  infects  all  milk  with  which  it  is  mixed. 
There  has  been  a  great  difference  of  opinion  as  to  the  proportion  of 
affected  cattle  which  yield  milk  containing  the  tubercle  bacilli.  Some 
have  held  that  the  udder  must  necessarily  be  diseased  before  the  bacilli 
can  find  their  way  into  the  milk  ducts,  and  as  only  a  small  proportion 
of  the  affected  cows  have  disease  of  the  udder,  the  danger  from  this 


32  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

source  was  thought  to  be  slight.  It  seems  likely,  however,  that  the 
udder  is  affected  in  a  larger  number  of  cases  than  has  usually  been 
admitted.  It  requires  a  very  long  and  careful  examination  to  deter- 
mine positively  that  the  udder  is  free  from  the  disease.^  The  European 
statistics  have  usually  given  the  proportion  of  udder  tuberculosis  as 
from  1£  to  3  per  cent  of  the  total  number  of  cases;  but  Pearson,  in  the 
examination  of  1,200  tuberculous  cows  in  Pennsylvania,  found  the 
udder  affected  in  8.75  per  cent  of  the  animals. 

Numerous  investigations  have  also  shown  that  milk  may  contain 
tubercle  bacilli  when  there  are  no  appreciable  signs  of  tubercular 
disease  in  the  udder.  A  few  of  the  more  striking  of  these  may  be 
mentioned.  Bang27  tested  the  milk  of  21  tuberculous  cows  with  nor- 
mal udders  by  inoculating  48  rabbits.  Two,  or  9.5  per  cent,  of  these 
cows  transmitted  the  disease.  Later  he  injected  40  guinea  pigs  with 
milk  from  28  cows  affected  with  generalized  tuberculosis  and  showed 
that  virulent  milk  was  being  secreted  by  4  of  these  animals,  3  of  which 
on  post-mortem  examination  were  found  to  have  lesions  in  the  udder. 
By  intra-abdominal  inoculations  of  28  guinea  pigs  with  the  milk  of  14 
tuberculous  cows  he  found  that  3  of  the  latter  were  excreting  tubercle 
bacilli  in  their  milk.  The  summary  of  these  experiments  shows  that  of 
63  cows  9  gave  virulent  milk,  and  of  this  number  3  had  tuberculous 
udders,  leaving  9.5  per  cent  of  the  cows  with  normal  udders  producing 
infectious  milk.28 

Ravenel 2  experimented  with  5  cows  which  reacted  to  tuberculin  but 
showed  no  physical  signs  .of  tuberculosis.  The  udders  in  every  case 
were  free  from  disease  so  far  as  a  careful  inspection  could  reveal.  The 
post-mortem  examination  of  these  cows  confirmed  the  diagnosis  made 
during  life.  He  inoculated  guinea  pigs  with  a  single  dose,  averaging 
10  c.  c.  of  milk  from  these  cows.  In  the  first  series  of  experiments  4 
out  of  31  guinea  pigs,  or  12.9  per  cent,  became  tuberculous.  In  the 
second  series  of  experiments  5  out  of  24  guinea  pigs  contracted  tuber- 
culosis, a  percentage  of  20.8.  In  the  third  series,  in  which  the  milk 
of  a  single  cow  was  employed,  1  guinea  pig  out  of  8  became  tuberculous, 
or  12.5  per  cent.  In  these  three  series  of  experiments  10  guinea  pigs 
out  of  63,  or  15.8  per  cent,  became  infected  by  a  single  dose  of  milk 
from  these  cows  which  apparently  had  no  disease  of  the  udder. 

Rabinowitsch89  and  Kempner  succeeded  in  producing  tuberculosis 
in  guinea  pigs  with  the  milk  of  10  out  of  15  tuberculous  cows,  or  66.6 
per  cent.  Two  of  these  cows  were  later  found  to  have  tuberculous 
udders,  3  showed  advanced  generalized  tuberculosis,  while  the  remaining 
5  animals  were  but  slightly  affected.  The  writers  conclude  that  milk 
from  cows  with  incipient  tuberculosis,  but  without  disease  of  the  udder, 
may  contain  tubercle  bacilli;  also  that  in  latent  forms  of  tuberculosis 
the  milk  may  prove  infectious,  although  the  cow  may  not  present  any 
clinical  symptoms  of  tuberculosis;  and  therefore  that  milk  from  all 
cows  reacting  to  tuberculin  should  be  considered  as  at  least  suspicious. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  33 

It  is  believed  by  Adarai30  that  the  cells  of  an  actively  secreting 
mammary  gland  of  a  cow  can  take  up  and  discharge  the  tubercle 
bacilli  without  the  animal  showing  any  lesion  of  the  lacteal  tract.  He 
and  Martin  examined  the  milk  of  10  cows,  and  when  these  were  killed 
the  udders  were  subjected  to  microscopic  examination  with  negative 
results.  In  the  milk  of  6  (60  per  cent)  of  these  cows  tubercle  bacilli 
were  observed  by- the  aid  of  the  microscope.  The  milk  from  the  cow 
showing  the  greatest  number  of  bacilli  was  inoculated  into  2  guinea 
pigs,  and  both  died  as  a  result  of  the  infection.  Twent\T-nine  guinea 
pigs  and  26  rabbits  were  inoculated  with  varying  quantities  of  milk, 
and  1  calf  was  fed  for  five  months,  but  only  2  guinea  pigs  died  of 
tuberculosis. 

Gehrman  and  Evans31  found  tubercle  bacilli  in  the  milk  of  15  out  of 
41  cows  with  sound  udders,  or  36.6  per  cent.  Guinea  pigs  inoculated 
with  milk  from  10  of  these  cows  died  of  tuberculosis  (24.3  per  cent). 
Their  final  showing  is  that  16  of  the  cows,  or  39  per  cent,  at  one  time 
or  another,  gave  milk  containing  tubercle  bacilli. 

The  milk  of  56  reacting  cows  which  showed  no  signs  of  disease  of 
the  udder  was  carefully  tested  in  various  ways  by  Mohler  and 
Norgaard.32  One  or  more  of  the  guinea  pigs  fed  with  milk  from  9 
different  cows  out  of  this  lot  succumbed  to  typical  tuberculosis — that 
is,  the  milk  of  16.07  per  cent  of  the  56  reacting  cows  was  found  to  be 
pathogenic  to  guinea  pigs  when  fed  to  them. 

Of  the  experimental  animals  inoculated  intra-abdominally  in  the  first 
series,  at  least  1  guinea  pig  died  of  tuberculosis  in  each  of  six  dif- 
ferent instances,  showing  that  the  milk  of  10.9  per  cent  of  the  55 
reacting  cows  in  this  experiment  was  fatal  to  guinea  pigs.  In  the 
second  series  of  intra-abdominal  injections,  the  milk  from  7  individual 
cows  out  of  45  examined,  or  15.5  per  cent,  was  demonstrated  to  pos- 
sess virulent  tubercle  bacilli.  By  uniting  these  inoculation  results,  it 
is  found  that  11  out  of  55  cows,  or  20  per  cent,  secreted  milk  which 
transmitted  tuberculosis  to  one  or  more  experimental  animals  when 
injected  into  the  peritoneal  cavity. 

The  combined  results  of  the  ingestion  and  inoculation  experiments 
showed  that  the  milk  of  12  out  of  56  reacting  cows,  or  21.4  per  cent, 
at  one  time  or  another,  during  the  experiment  contained  virulent 
tubercle  bacilli. 

Specimens  of  the  mammary  glands  from  all  the  cows  yielding  this 
virulent  milk  were  brought  to  the  laboratory  and  histological  exami- 
nation was  made  of  them  without  finding  any  indication  of  tuberculosis. 
With  one  of  these  cows  positive  results  were  obtained  in  all  of  the 
tests — that  is,  by  ingestion,  by  inoculation,  and  by  miscroscopic 
examination  of  the  sediment  of  the  milk  and  cream — although  but  7 
of  the  10  experimental  animals  fed  and  inoculated  with  the  milk  of 
this  cow  became  tubercular.  It  was  evidently  a  case  in  which  the  milk 
1881— No.  38—06 3 


34  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

was  seriously  contaminated.  Special  attention  was  given  to  the  exami- 
nation of  the  udder  of  this  cow  and  numerous  serial  sections  were 
examined,  with  entirely  negative  results. 

The  results  of  these  careful  experiments  prove  that  the  milk  from 
a  considerable  proportion  of  reacting  cows  contains  the  tubercle 
bacillus  and  is  capable  of  producing  tuberculosis  in  animals  which 
consume  it.  The  proportion  of  cows  which  yield  such  infected  milk 
is  much  greater  than  the  proportion  which  show  tuberculosis  of  the 
udder.  Whether  the  milk  in  these  cases  was  actually  infected  within 
the  udder  or  whether  it  became  contaminated  at  the  time  it  was  drawn 
makes  little  practical  difference.  Every  precaution  was  taken  to  pre- 
vent such  contamination  after  the  milk  left  the  mammary  gland,  and 
if  the  bacilli  floating  in  the  air  of  the  infected  premises  or  dropping 
from  the  coats  of  the  animals  infected  the  milk  in  spite  of  the  precau- 
tions that  were  taken,  similar  infection  would  certainly  occur  in 
ordinary  dairy  operations.  It  must  be  admitted,  therefore,  that  the 
milk  from  tuberculous  cows  is  often  infected  and  dangerous  when,  so 
far  as  can  be  ascertained,  the  udder  is  in  a  normal  condition. 

The  milk  from  tuberculous  herds  is  a  frequent  source  of  tubercu- 
losis in  calves  and  pigs.  The  calves  born  in  tuberculous  herds  are  fed 
upon  the  milk  produced  by  such  herds  during  the  early  period  of  their 
lives,  and  a  considerable  proportion  of  them  may  be  infected  in  that 
way.  In  dairies  where  butter  is  made,  or  from  which  cream  is  sold, 
the  skim  milk  is  commonly  fed  to  pigs,  and  in  other  cases  skim  milk 
is  obtained  from  creameries  for  feeding  to  calves  and  pigs,  and  the 
animals  are  often  infected  in  this  way. 

Pearson  and  Ravenel,2  in  treating  of  the  ways  in  which  tuberculosis 
may  be  spread,  say  that  the  mixed  skim  milk  returned  from  a  creamery 
to  a  healthy  herd  may  be  contaminated.  This  danger  is  so  great  that 
in  some  places  (parts  of  Pennsylvania  and  New  England,  France,  and 
German}^)  it  is  the  practice  to  heat  skim  milk  to  a  temperature  that 
will  insure  the  destruction  of  the  tubercle  bacillus.  In  Denmark  and 
Prussia  such  heating  of  skim  milk  and  buttermilk  is  required  by  law. 
Several  illustrations  of  this  danger  had  recently  come  under  the  obser- 
vation of  these  authors.  In  one  case  a  large  herd  was  tested  with 
tuberculin  an'd  found  to  be  extensively  diseased.  Two  of  the  cows  had 
tubercular  udders.  This  herd  was  used  for  the  production  of  cream  that 
was  shipped  to  market,  the  skim  milk  being  retained  for  feeding  calves. 
It  was  the  practice  on  this  farm  to  remove  the  calves  from  their  dams 
when  they  were  three  days  old  and  keep  them  in  a  separate  building 
distant  from  the  cow  stable.  The  dairy  building  and  separator  were 
located  midway  between  the  cow  stable  and  the  calf  stable.  After 
the  cream  had  been  separated  the  skim  milk  was  carried  on  for  the 
calves.  When  the  cows  were  tested  the  calves  were  also  examined, 
and  it  was  found  that  while  the  prevalence  of  tuberculosis  among  the 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS. 


35 


dairy  cows  was  75  per  cent,  all  the  calves  reacted  and  were  condemned. 
The  post-mortem  examinations  of  the  calves  revealed  tuberculosis  of 
the  postpharyngeal  lymphatic  glands  or  lower  digestive  tract  in  all 
cases,  indicating  that  infection  had  occurred  through  the  digestive 
system  and  that  it  had  been  carried  to  these  calves  in  skim  milk. 

Only  a  small  proportion  of  the  calves  dropped  by  tuberculous 
mothers  are  affected  with  tuberculosis  at  the  time  of  birth.  In  other 
words,  the  cases  of  congenital  tuberculosis  are  very  rare.  Klepp 
found  at  the  slaughterhouse  in  Kiel  among  4,068  calves  that  were 
slaughtered  only  26  affected,  or  0.64  per  cent,  and  in  a  second  series 
of  investigations  there  were  found  10  calves  affected  with  congenital 
tuberculosis  among  847,  a  proportion  of  1.18  per  cent.  Hoy  berg 
obtained  similar  results,  having  found  6  cases  of  congenital  tuberculo- 
sis among  500  calves  examined  at  the  time  of  slaughter.  According 
to  the  calculations  of  Klepp  only  2.63  per  cent  of  the  calves  dropped 
by  tuberculous  mothers  are  affected  with  congenital  tuberculosis.33 

As  an  example  of  the  proportion  of  calves  found  affected,  Bang22 
gives  the  statistics  of  the  small  slaughterhouse  at  Aarhus,  Jutland, 
where  very  careful  examinations  are  made  and  where  the  cattle  come 
from  a  district  in  which  tuberculosis  is  very  widely  distributed.  In 
the  year  1903  there  were  found  among  0,765  calves  (3,279  quite  young 
calves  and  3,484  fat  calves)  100,  or  1.48  per  cent,  tuberculous  (with  14 
new-born  calves  the  existence  of  congenital  tuberculosis  was  discov- 
ered). Among  4,920  grown  cattle  there  were  2,509  tuberculous,  or 
51  per  cent. 

It  would  appear  from  these  figures  that  possibly  not  more  than 
1  per  cent  of  the  calves  from  tuberculous  mothers  are  affected  with 
tuberculosis  at  the  time  of  birth.  In  very  badly  affected  herds  as  high 
as  2  per  cent  of  the  calves  may  have  congenital  tuberculosis.  Under 
any  circumstances,  it  is  plain  that  the  great  majority  of  calves  contract 
the  disease  either  from  contaminated  milk  or  from  inhabiting  the  stables 
where  tuberculous  cows  are  kept. 

Bang22  gives  the  following  table  showing  the  distribution  of  tuber- 
culosis according  to  age  in  40,624  cattle  tested  for  the  first  time  in 
Denmark  during  the  years  1898-1904: 


Age  when  tested. 

Number 
tested. 

Number 
which 
reacted. 

Percent. 

Calves  up  to  one-half  vear         

5  559 

675 

12  1 

Cattle  from  one-half  to  1J  years  

7  744 

2,  129 

27  5 

Cattle  from  H  to  2J  years  

5,  047 

1,949 

38.6 

Cattle  from  2}  to  5  vears.                 . 

10  350 

4  644 

44  9 

Cattle  over  5  vears  

11,924 

6,724 

48.0 

Total  

40  624 

15  121 

37.2 

This  table  shows  that,  in  a  country  where  from  45  to  48  per  cent  of 
the  adult  cattle  are  tuberculous,  12.1  per  cent  of  the  calves  are  affected 
by  the  time  they  are  six  months  old.  If  2  per  cent  of  these  calves 


36  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS.' 

have  congenital  tuberculosis  it  follows  that  more  than  10  per  cent  of 
them  contract  the  disease  from  the  milk  which  they  drink  or  from  the 
infected  stables  in  which  they  are  kept.  During  the  second  half  year 
of  the  life  of  the  animals  an  additional  15  per  cent  become  infected. 
Probably  the  greater  part  of  the  infections  during  the  first  year  result 
from  contaminated  food.  These  statistics,  therefore,  show  the  impor- 
tant role  played  by  infected  milk  as  a  disseminator  of  tubercular  disease. 
Phelps,24  of  the  Storrs  (Conn.)  Experiment  Station,  reports  the 
results  of  experiments  made  there  in  feeding  to  calves  the  milk  of 
tuberculous  cows: 

During  the  greater  part  of  the  four  years  that  4  tuberculous  cows  were  at  the  sta- 
tion the  milk  of  some  or  all  of  them  was  fed  to  calves.  The  results  of  the  first  two 
years'  feeding  show  that,  while  the  milk  of  each  of  the  4  cows  was  fed  to  several 
calves  in  periods  ranging  from  three  months  to  one  year  and  four  months,  in  no  case 
was  there  any  indication  of  disease  in  the  calves  during  the  feeding  period.  The 
calves  were  kept  with  the  cows  nearly  two  years.  One  of  these  calves  responded  to 
the  tuberculin  test  about  five  months  after  the  feeding  period  of  sixteen  months  was 
ended,  and  was  found  upon  post-mortem  examination  to  be  very  slightly  diseased. 

Two  calves,  the  offspring  of  tuberculous  cows,  were  selected  for  a  comparison  of 
the  infectiousness  of  pasteurized  and  raw  milk.  About  half  of  the  milk  of  1  cow 
was  heated  to  about  170°  F.  and  fed  to  her  offspring,  and  the  balance  of  the  milk  in 
its  natural  state  was  fed  to  the  offspring  of  the  other  tuberculous  cow.  The  calves 
were  isolated  from  the  cows.  Neither  of  the  calves  responded  to  a  tuberculin  test 
made  after  a  feeding  period  of  about  ten  months.  By  a  misunderstanding  both  of 
the  calves  were  fed  the  unpasteurized  milk  of  the  cow  for  a  period  of  three  weeks 
(following  the  tuberculin  test) ,  after  which  they  were  turned  out  to  pasture  for  about 
five  months.  Three  weeks  after  being  returned  to  the  stable  with  the  cows  the  calf 
which  had  been  fed  the  pasteurized  milk  (except  for  three  weeks)  responded  to  the 
tuberculin  test,  while  the  other  calf  failed  to  respond  until  five  months  later. 

Two  other  calves  were  fed  the  milk  of  their  dams  from  August  and  September, 
1898,  until  the  next  June.  At  the  end  of  ten  months'  feeding  in  one  case  and  nine 
and  one-half  in  the  other  neither  of  the  calves  responded  to  the  test.  One  calf  was 
at  pasture  from  June  24  to  November  13,  while  the  other  remained  in  the  stable  with 
the  cows.  Both  responded  to  the  test  on  December  2  following,  three  weeks  after 
one  of  the  calves  was  returned  from  the  pasture. 

Two  more  calves  were  fed  the  milk  of  the  2  other  cows.  Both  had  tuberculous 
mothers.  One  was  kept  in  the  stable  with  the  cows,  and  after  being  fed  the  milk  of 
cow  No.  1344  for  a  period  of  ten  weeks  responded  to  the  tuberculin  test.  The  other 
was  fed  the  milk  of  its  dam  (No.  1343)  while  isolated  in  a  room  in  another  part  of 
the  barn.  After  a  feeding  period  of  nearly  three  months  this  calf  responded  to  the 
tuberculin  test. 

Three  other  calves  from  nontuberculous  cows  were  selected  early  in  May,  1900, 
and  placed  in  a  small  pasture  near  the  station  barn.  Calf  L  was  fed  the  milk  of 
No.  1337,  calf  M  the  milk  of  No.  1341,  and  calf  N  the  milk  of  No.  1343.  All  prac- 
ticable precautions  were  taken  to  prevent  the  transmission  of  the  disease  in  any  way 
except  by  the  milk.  The  calves  were  tested  May  24-25,  about  three  weeks  after  the 
feeding  began,  and  again  September  28-29,  after  having  been  fed  over  four  and  one- 
half  months.  None  of  the 'calves  responded  to  either  test.  The  calves  were  not  fed 
milk  after  the  September  test  but  were  kept  isolated  from  the  cows.  Calf  M  died 
November  29,  and  an  examination  by  the  station  veterinarian  revealed  a  congested 
condition  of  the  stomach,  kidney,  and  bladder,  indicating  some  form  of  poisoning. 
An  examination  of  the  lungs  also  demonstrated  the  existence  of  tuberculosis,  there 
being  a  tuberculous  nodule  in  the  right  lung,  calcified,  and  the  mediastinal  lym- 
phatic being  tuberculous.  The  two  remaining  calves  failed  to  respond  to  a  tuber- 
culin test  in  February,  1901,  and  in  May  were  sent  to  pasture  with  some  other  stock. 

Thus  in  the  first  feeding  test  1  calf  out  of  several  became  tuberculous,  and  in  the 
four  succeeding  tests  7  out  of  9  eventually  became  tuberculous.  The  2  which  did 
not  respond  to  the  test  may  or  may  not  nave  been  diseased.  The  uncertainty  of 
depending  upon  repeated  tuberculin  tests  in  such  cases  is  shown  by  the  last- 
mentioned  experiment,  in  which  no  tuberculosis  would  have  been  found  had  it  not 
been  for  the  accidental  death  of  one  of  the  calves.  Some  of  these  calves  may  have 
been  infected  through  cohabitation,  but  in  any  case  the  large  proportion  of  infection 
shows  the  danger  of  having  tuberculous  cows  in  a  herd. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  87 

SPREAD   OF   TUBKKCULOSIS   FROM    DISEASED   TO    HEALTHY    CATTLE. 

The  rapid  tind  widespread  dissemination  of  the  disease  by  the  sale  of 
breeding  stock  from  tubercular  herds  has  been  pointed  out  by  Russell 
and  Hastings.3* 

Where  the  disease  establishes  itself  in  herds  that  are  sold  for  breeding  purposes 
the  danger  is  much  increased,  for  animals  from  such  sources  are  much  more  apt  to 
be  widely  disseminated,  since  they  generally  serve  as  a  foundation  for  the  breeding 
up  of  common  stock.  The  State  of  Wisconsin,  as  well  as  other  Northwestern  States, 
has  suffered  in  this  regard  very  severely  from  some  of  its  finest  breeding  herds.  One 
herd  in  particular  in  this  State  has  had  anything  but  an  enviable  record  in  this  mat- 
ter, for  it  has  been  determined  that  tuberculosis  has  broken  out  in  at  least  16  herds 
to  which  members  of  this  original  herd  were  sold.  While  it  can  not  be  proved  that  the 
origin  of  the  disease  in  each  of  these  16  cases  could  be  traced  to  the  animals  originally 
purchased,  yet  it  is  noteworthy  that  in  a  considerable  number  of  cases  the  firstanimals 
to  show  evident  symptoms  of  the  disease  were  those  that  were  introduced  from  this 
badly  diseased  herd.  Not  only  were  a  number  of  tine  herds  in  Wisconsin  infected 
from  this  source,  but  the  contagion  was  also  spread,  in  a  number  of  cases,  to  Minne- 
sota and  Iowa. 

Schroeder  and  Cotton35  have  made  experiments  to  test  the  rapidity 
witli  which  tuberculosis  spreads  in  a  stable  from  diseased  to  healthy 
cattle. 

Seven  healthy  cattle  and  3  tubercular  cows  were  confined  in  a  stable  containing 
10  box  stalls,  which  were  separated  by  solid  2-inch  plank  partitions  6  feet  high. 
Five  of  the  healthy  cattle  and  the  3  tuberculous  cows  occupied  different  stalls 
each  day,  in  a  rotation  which  exposed  each  of  the  healthy  cattle  equally  to  the  3  dis- 
eased cows.  Two  of  the  healthy  cattle  occupied  stalls  near  the  center  of  the  stable 
and  were  at  no  time  allowed  to  enter  other  stalls  or  to  come  into  closer  contact  with 
any  of  the  other  cattle. 

Two  and  one-half  months  after  the  beginning  of  the  experiment  1  of  the  3  tuber- 
culous cows  was  removed  from  the  stable,  and  2  other  and  more  severely  affected 
cows  were  introduced.  One  of  these  tuberculous  cows  died  after  it  had  been  in  the 
stable  two  months,  and  was  found  to  be  affected  with  generalized  tuberculosis,  but 
without  disease  of  the  udder  or  lymph  glands  associated  with  or  near  the  udder. 
All  of  the  exposed  cattle  were  tested  with  tuberculin  at  the  beginning  of  the  experi- 
ment and  found  to  be  free  from  tuberculosis. 

The  experiment  began  January  27,  1903,  and  the  exposed  cattle  were  tested  with 
tuberculin  on  June  30  following.  The  two  animals  which  had  been  confined  to 
their  stalls  were  a  yearling  bull,  which  reacted  to  the  last  test,  and  a  6-year-old 
cow,  which  did  not  react.  Both  animals  were  found  tuberculous  when  killed  and 
examined  August  3, 1903.  In  the  bull  the  posterior  mediastinal  glands  were  slightly 
enlarged  and  contained  numerous  small  recent  foci  of  tuberculosis.  The  anterior 
mediastinal  glands  were  greatly  enlarged  and  filled  with  foci  of  tubercular  material, 
and  the  bronchial  glands  contained  several  small  foci  of  recent  tubercular  disease. 
The  cow  also  was  diseased,  having  several  of  the  mediastinal  glands  greatly  enlarged 
and  thickly  sprinkled  with  small  tubercular  nodules,  recent  in  character,  and,  in 
addition,  several  small  recent  areas  of  tubercular  disease  scattered  through  the  lung. 

Two  heifers,  1  six  months  old  and  1  eighteen  months  old,  both  in  good  condition, 
were  made  to  occupy  a  different  stall  each  day  in  order  that  they  might  be  exposed 
equally  to  each  of  the  tuberculous  cows.  When  tested  with  tuberculin  on  June  30 
both  reacted.  Post-mortem  examination  of  the  younger  animal  showed  the  left 
principal  lobe  of  the  lung  adherent  to  the  chest  wall  and  near  the  adhesion  a  tuber- 
culous nodule  in  the  lung  tissue  about  1  inch  in  diameter.  The  anterior  and  posterior 
mediastinal  glands,  the  bronchial  gland*,  and  the  lymph  glands  about  the  root  of 
the  tongue  were  greatly  enlarged  and  either  entirely  tubercular  or  thickly  sprinkled 
with  minute  tubercular  foci.  Several  of  the  mesenteric  lymph  glands  were  con- 
verted to  the  extent  of  half  of  their  substance  into  tubercular  material,  and  a  num- 
ber of  other  mesenteric  glands  were  affected,  as  were  also  the  glands  at  the  brim  of 
the  pelvis  in  the  abdominal  cavity.  The  lesions  were  all  of  comparatively  recent 
origin.  The  older  heifer  had  one  small  focus  of  tubercular  disease  in  the  left  prin- 
cipal lobe  of  the  lung,  and  sprinkled  over  various  portions  of  the  pulmonary  pleura 
of  the  right  principal  lobe  of  the  lung  were  numerous  tubercles  with  corresponding 
tubercles  on  the  costal  pleura.  The  pulmonary  surface  of  the  diaphragm  was 


88  TUBERCULOSIS    OF    THE    FOOD-PBODUOING    ANIMALS. 

sprinkled  with  numerous  small  tubercles,  and  the  various  lobes  of  the  lung  were 
adherent  to  each  other  and  to  the  diaphragm  by  means  of  tissue  containing  many 
tubercles.  The  appearances  were  typical  of  pearl  disease  in  cattle. 

Three  other  cattle  were  exposed  in  the  same  manner  as  the  2  just  described,  but 
these  had  previously  been  given  intravenous  injections  of  dead  or  living  tubercle 
cultures.  One  of  these,  a  bull  calf  six  months  old,  had  20  c.  c.  of  dead  culture  of 
human  origin  injected  into  the  right  jugular  July  12,  1902,  and  at  the  beginning  of 
this  experiment  was  in  good  condition  and  gave  no  reaction.  When  tested  June  30, 
1903,  it  reacted,  and  on  post-mortem  examination  tubercular  deposits  were  found  in 
the  anterior  and  posterior  mediastinal  glands,  while  the  lymph  glands  back  of  the 
pharynx  were  five  times  their  usual  size  and  completely  tuberculous.  There  were 
also  a  number  of  recent  tubercular  foci  in  the  liver.  The  second  animal,  a  heifer 
calf  about  four  and  one-half  months  old,  had  received  in  the  right  jugular  20  c.  c.  of 
dead  bovine  tubercle  culture  July  19,  1902.  This  animal  was  also  in  good  condition 
and  failed  to  react  at  the  beginning  of  the  present  experiment.  When  tested  June 
30,  1903,  she  gave  a  marked  reaction.  She  was  slaughtered  and  examined  August 

5,  1903,  at  which  time  there  was  found  tuberculosis  of  the  mediastinal  and  bronchial 
glands  and  of  one  mesenteric  gland.      The  third  animal  of  this  group  was  a  cow 
about  two  years  old.     This  animal  had  received  injections  of  10  c.  c.  each  of  moder- 
ately virulent  human  tubercle  culture  into  the  right  jugular  vein  on  July  19,  August 

6,  August  20,  September  20,  and  October  7,  1902.     When  admitted  into  this  experi- 
ment, January  27,  1903,  she  looked  thin  and  unthrifty,  but  failed  to  react.      She 
also  failed  to  react  to  the  test  of  June  30,  1903.     Killed  and  examined,  August  6, 
1903,  the  entire  lung  was  found  to  be  sprinkled  with  minute  white  nodules,  having 
an  appearance  similar  to  that  observed  on  several  occasions  after  the  injection  of 
human  tubercle  into  the  veins  of  cattle.     No  tuberculous  lesions  were  found  in  other 
parts  of  the  body,  and  the  disease  in  this  animal  was  undoubtly  caused  by  the 
injections  of  the  cultures  of  human  bacilli. 

The  rapidity  with  which  tuberculosis  spreads  in  stables  occupied  b}' 
tuberculous  cattle  is  shown  with  particular  emphasis  by  the  two  cattle 
which  became  tuberculous  without  actual  contact  with  the  tuberculous 
cows  and  while  standing  in  stalls  which  were  separated  from  the  other 
stalls  by  solid  partitions  6  feet  high.  The  distribution  of  the  lesions 
indicate  that  the  germs  of  tuberculosis  in  stable  infection  are  more 
commonly  respired  than  ingested  with  food.  This  experiment  clearly 
shows  that  cattle  can  not  be  protected  from  tuberculosis  when  in  the 
stables  with  tuberculous  cattle,  even  when  each  animal  is  carefully 
restricted  to  its  own  individual  stall. 

THE   EFFECT   OF   INSANITARY   CONDITIONS. 

The  ideal  conditions  for  health  and  for  resistance  to  the  tuberculosis 
contagion  are  life  in  the  open  air  and  an  abundant  supply  of  nutritious 
food.  The  greater  the  departure  made  from  these  ideal  conditions, 
the  more  is  the  development  of  tuberculosis  favored.  At  the  same 
time  it  should  be  remembered  that  this  disease  will  not  appear  in  an 
animal  unless  the  tubercle  bacillus  has  gained  entrance  to  its  tissues, 
and  this  bacillus  can  not  originate  in  a  stable,  no  matter  how  insanitary 
its  conditions  may  be.  The  tubercle  bacillus,  like  other  forms  of  liv- 
ing things,  must  come  from  a  preexisting  germ  of  the  same  species; 
and  as  it  grows  only  in  the  body  of  an  animal,  it  must  be  transported 
in  some  manner  from  a  diseased  animal  to  a  healthy  one  before  the 
latter  can  contract  the  disease.  These  are  foundation  principles  which 
are  thoroughly  established  and  which  must  be  borne  in  mind  in  han- 
dling animals  for  the  prevention  or  the  suppression  of  tuberculosis. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  39 

Life  in  the  open  air  is  not  always  sufficient  to  prevent  infection  with 
tuberculosis  or  to  cure  animals  that  are  already  affected  by  it,  but  its 
influence  is  favorable  and  reduces  the  chances  of  infection  to  the  small- 
est proportion,  while  at  the  same  time  it  places  the  diseased  animal 
under  the  best  conditions  for  its  recovery.  In  most  stables  the  condi- 
tions of  life  are  radically  different  from  what  they  are  in  the  open  air. 
It  is  only  necessary  to  make  the  most  casual  inspection  of  the  ordinary 
stable  to  assure  oneself  that  the  conditions  of  life  there  are  unfavor- 
able in  the  extreme. 

Ventilation. — Most  stables  have  no  provision  for  ventilation.  Any 
air  which  enters  them  must  come  through  the  doors  or  the  walls  of  the 
buildings;  either  there  are  drafts  of  air  upon  the  animals,  favoring 
the  production  of  colds  and  catarrhs,  or  there  is  an  insufficient  supply 
of  oxygon.  The  circulation  of  pure  air  in  a  stable  furnishes  an  abun- 
dant supply  of  oxygen,  which  increases  the  resisting  powers  of  the 
animal,  and  it  also  serves  to  carry  away  dust  and  other  impurities 
which  may  be  floating  in  the  atmosphere  of  the  stable.  Where  there 
is  no  ventilation  disease  germs  carried  into  a  stable  are  likely  to  remain 
there  until  they  infect  the  animals.  Where  there  is  little  ventilation 
stables  are  almost  always  damp,  and  such  dampness  favors  the  preser- 
vation of  the  bacilli  and  tends  to  the  production  of  catarrh  in  the  air 
tubes  of  the  animals,  which  is  a  condition  favorable  for  the  lodgment 
of  these  germs.  Tuberculosis  is  most  frequent  with  people,  as  well  as 
with  animals,  who  are  crowded  together  in  small  and  poorly  ventilated 
quarters.  An  abundant  supply  of  fresh  air  in  the  stable  acts  favorably 
in  several  ways:  First,  it  is  a  means  of  supplying  the  animals  with  a 
proper  amount  of  oxygen  for  carrying  on  the  functions  of  their  bodies; 
second,  the  circulating  air  carries  away  the  carbon  dioxide  and  the 
moisture  given  off  from  the  animals"  bodies,  and  leaves  the  stables  dry 
and  healthful;  third,  the  air  currents' also  carry  away  bacteria  of  all 
kinds  which  may  be  floating  in  the  atmosphere  of  the  stable,  and  in 
that  way  they  reduce  the  chances  of  infection;  and,  fourth,  fresh  air 
and  dryness  are  unfavorable  conditions  for  the  preservation  of  bacteria, 
and,  consequently,  well-ventilated  stables  are  not  so  easily  infected  as 
others,  and  the  infection  dies  out  more  readily  in  them. 

Light. — It  is  just  as  desirable  that  there  should  be  ample  provision 
to  let  light  into  a  stable  as  that  there  should  be  ventilation.  The 
direct  rays  of  the  sun  are  of  especial  value  for  destroying  tubercle 
bacilli  and  for  increasing  the  resistance  of  the  animals  to  their  attacks. 
In  addition  to  this  the  sun^s  rays  aid  in  drying  and  disinfecting  the 
stable.  Light  is  also  necessary  to  enable  those  who  care  for  the  stable 
to  see  the  dust  and  tilth  and  to  put  it  into  proper  sanitary  condition. 
Dark  stables  are  almost  universally  dirty,  damp,  and  un healthful. 

Pearson  and  Ravenel 2  say  with  reference  to  this  subject  that— 

It  has  been  shown  by  Migneco,  Straus,  and  others  that  tubercle  bacilli  are  destroyed 
by  light  in  a  time  that  is  in  proportion  to  the  intensity  of  the  light  and  inversely  as 
the  thickness  of  their  protective  coating.  In  Migneco's  experiments  sputum  con- 


40  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

taining  many  bacilli  were  spread  out  on  linen  or  cotton  cloth  and  then  exposed  to 
sunlight.  Subsequently  .the  cloth  was  washed  in  sterile  water  and  the  wash  water 
was  injected  into  the  peritoneal  cavities  of  experimental  animals.  The  virulence  of 
the  germs  was  greatly  reduced  in  from  ten  to  fifteen  hours  and  when  the  layer  was 
not  too  thick  they  were  completely  destroyed  in  twenty-four  to  thirty  hours. 

Sunlight  has  a  decided  effect  on  the  chemical  processes  that  take  place  in  living 
tissues.  In  the  case  of  plants  this  is  very  marked.  Dammann  states  that  animals 
expire  smaller  quantities  of  carbon  dioxide  at  night  than  during  the  day.  Accord- 
ing to  the  experiments  of  Platin,  which  were  made  on  rabbits,  the  increase  in  oxygen 
consumption  and  in  carbon  dioxide  excretion  under  the  influence  of  light  is  from 
13  to  14  per  cent.  Dammann  calls  attention  to  the  fact  that  this  result  is  in  full 
accord  with  the  general  experience  that  animals  fatten  best  in  dark  stables,  and  it  is 
also  noticed  that  animals  kept  in  dark  places  for  long  periods  become  sluggish.  The 
pallor  that  is  characteristic  of  miners,  stokers  on  ocean  vessels,  and  prisoners  is  also 
due  to  the  absence  of  light.  In  darkness  there  appears  to  be  a  checking  of  the 
metabolism  and  tissue  change,  an  indolence  of  excretory  functions. 

De  Renzi  has  made  some  experiments  to  determine  the  effect  of  direct  sunlight  on 
tubercular  processes.  He  inoculated  8  guinea  pigs  with  tuberculous  sputum  and 
afterwards  placed  half  of  them  in  a  glass  box  and  the  others  in  a  wooden  box.  Both 
boxes  were  ventilated  from  below  and  were  placed  in  the  sun.  The  animals  in  the 
wooden  box  died  on  an  average  of  twenty-seven  days  after  the  inoculation,  while 
those  in  the  glass  box  lived  an  average  of  fifty-seven  days. 

Similar  experiments  have  been  made  in  the  laboratory  of  the  Pennsylvania  live 
stock  sanitary  board,  and  it  has  been  shown  that  light  prolongs  the  life  of  a  tubercular 
animal. 

Cleanliness. — A  stable  must  be  clean  in  order  to  be  sanitary. 
Cleanliness  is  the  first  principle  of  sanitation,  and  it  must  be  contin- 
ually kept  in  view.  Not  only  must  the  filth  on  the  surface  of  the 
floors  be  removed,  but  there  must  be  no  channels  by  which  it  can 
gather  between  or  beneath  the  flooring  to  ferment,  putrify,  and 
pollute  the  atmosphere  with  noxious  gases.  The  dust  which  gathers 
upon  the  walls  is  often  even  more  objectionable  than  the  filth  upon 
the  floors.  In  infected  stables  the  dust  is  certain  to  contain  tubercle 
bacilli,  and  these  are  in  a  condition  to  be  easily  floated  in  the  atmos- 
phere and  breathed  into  the  animals'  lungs.  A  stable  to  be  sanitary 
should  be  so  constructed  that  the  floors,  walls,  and  ceilings  may  be 
thoroughly  cleaned  and  disinfected.  It  should  be  free  from  cracks, 
inaccessible  ledges,  and  corners,  and  from  decayed  wood,  all  of  which 
may  harbor  contagion.  The  first  thing  is  to  have  the  stable  so 
constructed  that  it  is  possible  to  clean  it  thoroughly,  and  the  second 
thing  is  to  see  that  it  is  frequently  cleaned  and  that  it  is  occasionally 
disinfected.  If  there  are  tuberculous  cows  in  a  herd,  the  feed  boxes 
and  mangers  soiled  with  the  saliva  of  the  diseased  animals  are  the 
most  dangerous  parts  of  the  stable.  Next  to  these  are  the  parts 
covered  with  thin  layers  of  manure,  which  becomes  dry  and  pulverized 
and  is  carried  into  the  air  as  dust;  and  not  less  dangerous  is  the  dust 
which  has  accumulated  on  the  walls  and  in  every  part  of  the  stable 
where  it  can  lodge.  In  cleaning  such  a  stable  the  walls  and  ceilings 
should  be  swept  and  washed  as  weH  as  the  floors,  and  the  whole 
interior  should  be  drenched  with  the  disinfecting  liquid. 

To  be  in  a  sanitary  condition  a  stable  must,  therefore,  be  well  ven- 
tilated, but  free  from  strong  currents  of  air;  it  must  be  light  and 
permit  the  entrance  of  the  sun's  rays  during  at  least  a  part  of  the 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  41 

day;  it  must  be  dry,  with  no  stagnant  water  standing  under  or  near 
it;  and,  finally,  it  must  be  clean,  not  only  as  regards  the  accumulations 
of  manure  in  the  gutters,  but  as  to  the  less  noticeable  contaminations 
of  the  floors  and  walls. 

If  these  conditions  are  realized,  a  long  step  will  have  been  taken  in 
the  struggle  against  tuberculosis;  the  disease  will  not  spread  so  rap- 
idly in  such  a  stable  as  in  the  ordinary  kind,  and  it  will  be  far  more 
easy  to  eradicate  the  contagion  from  it.  But  no  matter  how  perfect 
the  stable  or  how  unimpeachable  the  condition  in  which  it  is  main- 
tained, there  is  still  danger  of  the  disease  spreading  if  a  tuberculous 
cow  is  brought  into  the  herd,  and  if  a  number  of  cows  have  become 
affected  these  animals  must  be  discovered  and  removed  before  the  dis- 
ease can  be  suppressed.  Tuberculosis  can  not  be  successfully  combated 
by  sanitary  conditions  alone. 

Dr.  Leonard  Pearson40  has  made  interesting  investigations  bearing 
upon  the  effect  of  bad  stabling  conditions  in  favoring  the  spread  of 
tuberculosis  among  cows. 

For  the  purpose  of  the  investigation  2  herds  were  established  of  6  cows  each. 
Four  in  each  herd  were  healthy  and  2  in  each  herd  were  tubercular.  One  herd  was 
kept  in  a  roomy,  light,  clean,  and  well-ventilated  stable.  The  stalls  and  partitions 
between  the  mangers  in  this  stable  were  so  constructed  that  the  cows  were  kept 
apart  from  each  other. 

The  other  stable  was  small,  close,  poorly  ventilated,  rather  dark,  and  not  especially 
clean.  The  cows  here  were  not  separated  by  stall  partitions,  and  they  were  all  fed 
from  the  floor  of  the  passageway  in  front  of  their  stalls. 

This  experiment  continued  for  five  hundred  and  thirteen  days,  or  about  seventeen 
months,  and  at  the  close  it  was  found  that  2  of  the  originally  healthy  animals  kept 
in  the  large  light  stable  had  contracted  tuberculosis,  and  the  other  2  of  the  originally 
healthy  cows  continued  sound.  Of  the  4  originally  healthy  cows  in  the  small  dark 
stable  all  had  contracted  tuberculosis.  The  progress  of  the  disease  in  each  infected 
animal  in  the  dark  stable  was  greater  than  in  the  infected  animals  in  the  light  airy 
stable. 

THE  DETECTION  OF  TUBERCULOSIS. 

The  detection  of  tuberculosis  in  an}'  other  way  than  by  the  tubercu- 
lin test  is  often  difficult  or  impossible  during  the  life  of  the  animal, 
in  the  case  of  a  herd  of  cattle  we  have  three  sources  of  information— 
the  symptoms  brought  out  by  a  physical  examination  of  each  of  the 
individual  animals,  the  tuberculin  test,  and  the  examination  of  the  car- 
casses of  such  animals  from  the  herd  as  die  of  disease  or  are  slaughtered. 
Each  of  these  sources  of  information  is  of  great  value,  and  none  of 
them  should  be  neglected  in  case  there  is  any  reason  to  suspect  the 
existence  of  the  disease. 

PHYSICAL   EXAMINATION. 

The  inspection  of  a  herd  of  cattle  affected  with  tuberculosis  fre- 
quently reveals  evidence  strongly  indicative  of  the  presence  of  the 
disease.  Some  of  the  animals  may  be  emaciated,  the  skin  tensely 
drawn  over  the  bones,  the  hair  standing  on  end,  rough,  and  lusterless. 
There  is  an  undue  amount  of  coughing  in  the  morning  when  the  ani- 
mals are  fed,  when  they  are  driven  out  of  the  stable  into  the  cold 


42  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

air,  after  drinking  cold  water,  or  when  they  are  made  to  take  rather 
violent  exercise.  The  tymphatic  glands  located  about  the  throat,  in 
front  of  the  .shoulder,  or  in  the  flank  may  be  enlarged.  If  the  his- 
tory of  the  herd  shows  that  occasionally  an  animal  lost  flesh,  yielded 
a  decreased  quantity  of  milk,  and  gradually  pined  away  until  it 
died  or  it  became  necessary  to  kill  it,  tuberculosis  should  be  suspected. 

In  examining  the  individual  animals  the  object  is  to  learn  the  con- 
dition of  the  organs  most  frequently  the  seat  of  tubercular  disease. 
As  the  lungs  are  affected  in  from  60  to  75  per  cent  of  the  cases,  these 
organs  should  receive  careful  attention.  With  tuberculosis  of  the 
lungs  the  most  prominent  symptom  is  a  cough;  this  is  persistent, 
short,  dry,  strong,  and  often  high  in  pitch,  almost  whistling.  As  the 
disease  advances  the  cough  is  more  prolonged,  violent,  convulsive,  and 
may  be  accompanied  by  protrusion  of  the  tongue.  Auscultation  re- 
veals various  modified  and  abnormal  sounds  in  the  lungs.  There  may 
be  friction  sounds,  the  result  of  disease  of  the  pleura,  increased  respi- 
ratory murmur  from  bronchial  irritation,  loss  of  respiratory  murmur 
from  large  tubercular  deposits  or  adhesions,  mucus  rales  from  the 
inspired  air  being  drawn  through  collections  of  mucus  in  the  air 
tubes,  and  whistling  sounds  from  thickening  of  the  walls  of  the  bron- 
chial tubes.  Percussion  over  the  chest  walls  may  in  some  cases  show 
abnormal  resonance  from  the  tubercular  deposits  causing  portions  of 
the  lungs  to  recede  from  the  ribs,  but  in  a  larger  number  of  cases 
there  are  areas  of  dullness  corresponding  to  tubercular  masses.  In 
many  cases  with  severe  lesions  of  the  lungs  no  satisfactory  evidence 
can  be  obtained  by  either  auscultation  or  percussion. 

The  mediastinal  glands  are  situated  between  the  lobes  of  the  lungs 
and  rest  upon  the  esophagus.  Very  often  in  tuberculosis  they  are  dis- 
eased and  enormously  enlarged,  and  in  such  cases  they  press  upon  the 
esophagus  and  cause  digestive  disturbance,  more  particularly  chronic 
bloating,  which  may  appear  regularly  soon  after  eating,  no  matter  what 
the  character  or  the  quantity  of  the  food  taken.  Habitual  bloating, 
when  the  food  is  of  good  quality  and  taken  in  proper  amount,  and  when 
there  is  no  other  evidence  of  disease  of  the  digestive  organs,  is  consid- 
ered strongly  indicative  of  tuberculosis  with  enlargement  of  these  glands. 

In  tuberculosis  of  the  stomach  and  intestines  digestion  is  more  or 
less  interfered  with,  the  appetite  becomes  poor  or  irregular,  and 
there  is  frequently  diarrhea,  or  diarrhea  alternated  with  constipation. 
There  may  al  >o  be  bloating  and  colicky  pains. 

With  tuberculosis  of  the  uterus  and  ovaries,  and  sometimes  with 
peritoneal  tuberculosis,  the  cow  remains  almost  constant!}'  in  heat,  but 
is  often  sterile.  When  the  postpha^ngeal  glands  are  affected  there 
is  interference  with  the  breathing,  which  becomes  harsh  and  loud; 
there  may  also  be  difficulty  in  swallowing.  It  is.  sometimes  possible 
to  feel  the  enlarged  glands  by  placing  one  hand  on  each  side  of  the 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  43 

throat  and  then  pressing  with  both  hands  over  the  region  of  the  throat 
above  the  larynx. 

In  case  tubercles  form  in  the  brain  or  spinal  cord  the  symptoms 
vaiy  somewhat  according  to  the  part  affected.  The  first  signs  are 
depression,  soon  followed  by  stiffness  and  unsteadiness  of  the  gait. 
The  animal  lies  down  a  great  deal  and  rises  to  its  feet  with  diffi- 
culty. As  the  disease  advances  there  may  be  cramps  of  the  muscles 
of  the  neck  and  local  paralysis,  causing  difficulty  of  swallowing.  The 
food  is  retained  a  long  time  in  the  mouth  and  is  finally  dropped  into 
the  manger.  Sometimes  the  symptoms  are  those  of  acute  meningitis, 
when  the  animal  is  nervous,  excitable,  frenzied,  and  may  have  con- 
vulsions and  coma.  Usually  the  spinal  cord  and  brain  are  affected  at 
the  same  time,  the  effect  of  disease  of  the  cord  being  to  make  locomo- 
tion more  and  more  difficult  and  to  bring  about  paraplegia  and  paraly- 
sis of  the  posterior  extremities. 

With  tuberculosis  of  the  tongue  the  lesions  may  be  localized  or 
disseminated  throughout  the  organ.  In  the  former  case  the  tongue 
preserves  its  mobilit}7,  but  on  examination  a  swelling  may  be  detected 
in  some  part  of  it,  which  is  hard  and  embedded  in  the  tissue.  As  the 
tubercular  process  advances  an  ulcer  forms  on  the  upper  surface  of 
the  tongue  over  the  swelling,  which  is  covered  with  a  firm  3Tellowish 
exudate.  When  the  tubercular  deposit  is  diffused  through  the  organ 
the  tongue  loses  its  mobility,  becomes  hard,  and  has  an  appearance 
similar  to  the  "wooden  tongue,"  which  occurs  in  actinomycosis.  The 
diagnosis  is  made  by  a  microscopical  examination  of  the  affected  tissues. 

Tubercular  inflammation  of  the  stifle  joint,  and  less  f  requently  of  other 
joints,  may  occur  during  the  progress  of  the  disease.  The  affected 
joint  is  swollen,  warm,  and  very  painful.  There  is  great  lameness 
and  the  animal  is  hardly  able  to  put  its  foot  to  the  ground.  Such 
inflammations  of  the  joints  in  cattle  and  hogs  should  lead  to  the  suspicion 
of  tuberculosis. 

Sometimes  the  tuberculous  process  is  localized  in  the  trachea  and 
larynx,  and  this  may  occur  either  in  connection  with  lesions  of  other 
organs  or  independent  of  them.  The  respiration  is  harsh  and  loud  and 
accompanied  by  a  mucus  rale  or  gurgling  sound  caused  by  the  accumu- 
lation of  mucus  in  the  trachea.  In  such  cases  there  is  a  frequent  and  trou- 
blesome cough  which  is  easily  excited  by  pulling  on  the  tongue  or  by 
slight  pressure  upon  the  larynx.  The  animal  stands  with  the  nose 
raised,  the  head  extended  upon  the  neck,  and  avoids  lateral  inovements 
of  the  head  and  neck  on  account  of  the  tenderness  of  the  affected  region. 

The  diagnosis  of  tuberculosis  of  the  udder  is  a  matter  of  extreme 
importance,  on  account  of  the  danger  from  infected  milk.  Great 
attention  has,  therefore,  been  given  to  this  subject  by  many  investi- 
gators. A  recent  and  very  minute  study  of  mammary  tuberculosis 
has  been  made  by  Ostertag,  Breidert,  Kaesewurm,  and  Krautstrunk, S8 


44  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

and  we  are  now  able  to  speak  with  some  confidence  both  as  to  the 
methods  of  examination  and  the  symptoms  which  are  usually  found. 
Tuberculosis  of  the  udder  is  indicated  by  swelling  and  hardening  of 
one  or  more  quarters.  It  usually  begins  in  one  of  the  posterior  quar- 
ters and  takes  a  chronic  course.  The  swelling  causes  the  teats  of  one- 
half  of  the  udder  to  assume  a  parallel  or  con  verging  direction,  instead 
of  diverging  from  one  another.  A  healthy  quarter  feels  soft  or  mod- 
erately linn  throughout;  in  milch  cows  the  normal  elastic  tissue  often 
contains  symmetrical,  firm  masses  of  varying  size  formed  by  the 
lobules  of  the  gland.  A  tuberculous  quarter  feels  irregular  from  the 
beginning  of  the  disease.  Certain  portions,  especially  toward  the  buck 
of  the  udder  and  over  the  milk  cisterns,  are  firm,  stiff,  or  as  hard  as 
wood.  The  firm  parts  form  more  or  less  sharply  margined  lobules,  dis- 
tinct from  the  normal  elastic  tissue.  The  tuberculous  swellings  in- 
grease  in  circumference,  and  in  time  their  surface  becomes  nodulated. 

When  the  udder  is  distended  the  tuberculous  swellings  are  often 
difficult  to  detect,  but  in  the  relaxed  condition  of  the  organ  after  milking 
this  difficulty  disappears.  The  swellings  are  painless  and  of  the  same 
temperature  as  their  surroundings.  The  milk  of  the  diseased  quarter 
may  remain  apparently  normal  for  weeks,  but  as  the  tuberculous  pro- 
cess extends  and  destroys  the  secreting  tissue  it  changes  in  appearance, 
becomes  thin,  flocculent,  and  finally  watery.  At  this  time  it  often 
exhibits  an  alkaline  reaction  instead  of  the  normal  neutral  reaction. 

In  exceptional  cases  tuberculosis  of  the  udder  may  commence  with, 
acute  inflammation,  or  may  for  a  time  assume  an  acute  course.  The 
lymphatic  glands  of  the  diseased  quarter  or  half  are  always  swollen. 
Their  condition  can  most  conveniently  be  examined  by  thrusting  the 
skin  covering  the  side  of  the  diseased  hind  quarter  upward,  toward 
the  flank,  with  the  index,  middle,  or  ring  finger,  and  palpating  the 
posterior  and  lateral  aspects  of  the  glands  in  question.  When  diseased, 
the  glands  are  found  to  be  enlarged  in  all  directions;  sometimes  their 
surface  is  nodulated. 

Disease  simulating  tuberculosis  of  the  udder  m&y  be  produced  by 
chronic  infection  with  streptococci  or  with  actinomyces.  In  the 
chronic  inflammation  due  to  streptococci  the  lymph  glands  are  greatly 
enlarged  but  are  not  nodulated.  In  actinomycosis  of  the  udder  the 
lymph  glands  are  seldom  much  enlarged. 

The  clinical  diagnosis  of  tuberculosis  of  the  udder  may  be  regarded 
as  assured  when  one  quarter  of  the  udder  and  its  attached  lymph 
glands  exhibit  firm,  hard,  nodulated  swellings  without  signs  of  inflam- 
mation. When  the  quarter  and  attached  lymph  glands  exhibit  only 
firm,  hard  swellings,  without  nodulation,  the  diagnosis  is  somewhat 
doubtful.  Suspicion,  however,  will  be  increased  if  the  milk  from  the 
suspected  quarter  is  of  apparently  normal  constitution,  or  appears, 
from  the  history,  to  have  been  of  normal  constitution  at  the  com- 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  45 

mencement  of  the  disease.  The  probability  of  tuberculosis  is  again 
increased  by  the  existence  of  any  other  clinical  indications  of  the  dis- 
ease, such  as  (1)  general  falling  off  in  condition;  (2)  continued  fever 
without  apparent  acute  disease;  (3)  painless  nodulated  swellings  of  the 
pharyngeal,  prescapular,  or  precrural  lymphatic  glands  without  symp- 
toms of  inflammation;  (4)  frequent,  spontaneous,  weak  cough,  and 
pneumonic  rales  without  apparent  acute  inflammation;  (5)  frequently 
recurring  tympanites  without  apparent  cause;  (6)  frequent  oestrum 
and  muco purulent  discharge  from  the  vagina;  (7)  reaction  to  the 
tuberculin  test.  In  rare  cases  symptoms  of  tuberculosis  of  the  brain 
and  tuberculosis  of  the  vagina  may  lend  additional  weight  to  the  sus- 
picion of  tuberculosis  of  the  udder. 

Portions  of  the  prescapular  and  precrural  glands  may  be  removed 
without  danger.  Removal  of  portions  of  the  mammary  lymph  glands 
is  somewhat  difficult  on  account  of  the  deeper  position  of  these  parts, 
but  is  also  without  danger.  Macroscopic  examination  of  such  frag- 
ments is  often  sufficient  to  reveal  the  tuberculous  nature  of  the  disease. 

As  a  rule,  bacteriological  examination  is  indispensable  for  the  con- 
clusive diagnosis  of  tuberculosis  of  the  udder.  Of  the  various  forms 
of  examination  undertaken  with  this  object,  inoculation  of  guinea  pigs 
with  suspected  milk  is  the  most  reliable.  One  cubic  centimeter  of 
milk  as  withdrawn  is  sufficient.  The  milk  should  be  injected  into  the 
muscular  substance  of  the  inner  and  posterior  surface  of  the  hind  limb. 
This  is  as  reliable  as  intraperitoneal  injection,  which  was  formerly  the 
most  widely  employed,  and  was  regarded  by  Rabinowitsch  as  the  most 
conclusive,  while  it  has  the  advantage  of  being  much  speedier.  The 
experimental  animal  can  be  killed  for  further  examination  as  soon  as 
the  lymph  glands  near  the  point  of  inoculation  appear  firm,  hard,  pain- 
less, and  enlarged  to  the  size  of  a  small  pea.  This  often  occurs  within 
ten  days  of  inoculation;  but  should  the  lymphatic  glands  not  become 
diseased,  the  experimental  animals  are  killed  six  weeks  after  inocula- 
tion. The  discover}'  of  tubercle  bacilli  in  the  enlarged  lymph  glands 
or  internal  organs  confirms  the  diagnosis.  Intramuscular  injection 
obviates  sources  of  error  due  to  the  pseudotuberculous  changes  which 
so  often  follow  intraperitoneal  injection  of  milk  accidentally  contain- 
ing acid-fast  pseudotubercle  bacilli.  The  entrance  of  acid-fast  bacilli 
(which,  by  the  way,  can  usually  be  recognized  as  such  on  account  of 
their  shape)  can  be  avoided  if,  before  withdrawing  the  milk,  the  udder 
be  washed  with  soap  and  water,  cleansed  with  50  per  cent  alcohol,  and 
rubbed  dry  with  sterilized  wadding.  The  first  10  c.  c.  at  least  of  the 
milk  should  be  thrown  away.  Finally,  the  intramuscular  method  has 
the  great  practical  advantage  over  the  intraperitoneal  that  much  fewer 
experimental  animals  die  from  intercurrent  diseases. 

Examination  of  the  milk  by  means  of  smear  preparations  and  the 
bacterioscopic  examination  of  harpooned  fragments  of  the  tissue  of 


46  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

the  udder  are  uncertain.  Despite  the  existence  of  the  disease,  a  con- 
siderable number  of  such  tests  may  fail.  This  conclusion,  at  least 
as  regards  smear  preparations,  is  in  harmon}r  with  the  reports  of 
Rabinowitsch  and  Miiller.  The  last  method  of  examination  is  only 
conclusive  when  it  yields  a  positive  result.  Nevertheless,  as  stated  by 
Bang  and  Miiller,  it  is  valuable  for  the  rapid  diagnosis  of  advanced 
tuberculosis  of  the  udder.  In  certain  exceptional  cases  harpooning 
of  the  udder  may  prove  more  reliable  than  inoculation.  For  bac- 
teriological examination  the  milk  should  be  passed  through  a  cen- 
trifugal separator  and  the  precipitate  used. 

Harpooning  necessitates  casting  the  animal.  By  carefully  disin- 
fecting the  skin  and  using  sterilized  instruments,  the  operation  is 
rendered  harmless  even  if  repeated  several  times.  The  skin  and  the 
fascia  of  the  udder  are  first  divided,  the  suspected  portion  of  the 
udder  grasped  with  the  hand,  the  harpoon  introduced  into  the  sup- 
posed diseased  part,  rotated  slightly,  and  rapidly  withdrawn.  A 
small  fragment  of  tissue  is  sufficient,  provided  a  tubercle  can  be  rec- 
ognized by  macroscopic  or  microscopic  examination.  Harpooning 
may  be  resorted  to  when  inoculation  has  failed  to  confirm  an  other- 
wise strong  suspicion  of  tuberculosis,  or  when  the  milk  has  ceased  to 
be  secreted  and  therefore  can  not  be  employed. 

In  advanced  cases  of  tuberculosis  of  the  udder  the  secretion  from 
the  diseased  quarter  may  be  virulent  even  when  diluted  to  the  extent 
of  1  to  1,000,000,000.  In  incipient  tuberculosis  of  the  udder,  and 
sometimes  in  advanced  cases,  the  number  of  bacilli  is  very  small  and 
the  virulence  of  the  milk  can  be  destroyed  by  dilution  to  a  greater 
degree  than  1  to  1,000. 

In  examining  nasal,  pharyngeal,  and  vaginal  discharges  for  tubercle 
bacilli  it  must  be  borne  in  mind  that  these  materials,  like  the  feces, 
contain  acid-fast  pseudotubercle  bacilli,  and,  therefore,  that  in  doubtful 
cases  the  results  must  be  checked  b}^  inoculation  experiments. 

With  hogs  the  symptoms  of  tuberculosis  brought  out  by  physical 
examination  are  usually  not  clear.  The  principal  symptoms  are  pro- 
gressive emaciation  and  irregular  diarrhea,  sometimes  accompanied  by 
a  cough.  In  most  cases  the  glands  of  the  neck  are  affected,  and  fre- 
quently their  enlargement  causes  a  very  apparent  swelling  of  the  neck. 
Very  often  there  is  tuberculosis  of  a  joint  and  consequent  lameness. 
Animals  showing  these  S37mptoms  should  be  regarded  as  suspicious. 

THE    TUBERCULIN   TEST. 

Tuberculin  is  a  product  of  the  growth  of  the  tubercle  bacillus.  It 
is  prepared  by  sterilizing,  filtering,  and  concentrating  the  liquids  in 
which  the  tubercle  bacillus  has  been  allowed  to  multiply  in  the  labora- 
tory. This  substance  was  first  made  and  studied  by  Koch,  and  it  was 
found  that  when  injected  into  the  tissues  of  a  tuberculous  animal  it  had 
the  effect  of  causing  a  decided  rise  of  temperature,  while  it  had  no  such 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  47 

effect  upon  animals  free  from  tuberculosis.  The  value  of  tuberculin 
for  revealing  the  existence  of  tuberculosis  was  tested  by  many  investi- 
gators during  the  years  1890  and  1891.  The  injection  of  this  new  drug 
was  at  once  recognized  as  a  most  remarkable  and  accurate  method 
for  the  detection  of  tuberculosis,  even  in  the  early  stages  and  while 
the  animal  appeared  to  be  in  perfect  health.  Our  knowledge  of  the 
tuberculin  test  was  built  up  through  the  most  careful  and  thorough 
scientific  experimentation  and  should  be  accepted  as  entirely  reliable. 

In  practice  the  tuberculin  test  is  conducted  by  first  taking  the 
temperature  of  the  animal  to  be  tested,  at  intervals  of  about  two 
hours,  a  sufficient  number  of  times  to  establish  the  normal  temperature 
of  the  body  under  the  ordinary  conditions  of  life.  The  proper  dose 
of  tuberculin  is  then  injected  under  the  skin  with  a  hypodermic  syringe. 
The  point  of  inoculation  is  not  essential,  but  the  side  of  the  neck  is 
usually  selected  for  convenience  and  because  of  the  thinness  of  the 
skin  of  that  region.  The  injection  is  preferably  made  late  in  the 
evening,  and  the  temperature  is  taken  every  two  hours  the  following 
da}',  beginning  earl}r  in  the  morning  and  continuing  until  late  in  the 
evening.  Do  Sehweinitz,  in  1896,  calculated  the  average  temperature 
of  about  1,600  tuberculous  cows  which  were  tested  with  tuberculin, 
and  from  this  average  it  appears  that  in  general  the  rise  of  tempera- 
ture begins  from  five  and  one -half  to  six  hours  after  the  tuberculin  is 
injected,  reaches  its  greatest  height  from  the  sixteenth  to  the  twentieth 
hour,  and  then  gradually  declines,  reaching  the  normal  temperature 
again  by  the  twenty-eighth  hour.  When  a  chart  is  made  showing 
graphically  this  gradual  rise  and  decline  of  the  animal's  temperature 
after  it  has  been  injected  with  tuberculin,  we  have  what  is  called  the 
tuberculin  curve. 

In  studying  the  variations  of  temperature  which  followed  the  injec- 
tion of  tuberculin  into  health}"  and  tuberculous  cattle  it  was  found  that 
in  order  to  diagnose  tuberculosis  safely  there  should  be  a  rise  of  tem- 
perature of  not  less  than  2°  F.,  also  that  the  temperature  should  at  its 
highest  point  reach  about  104°  F.  To  avoid  errors  it  was  found  to  be 
important  that  a  full  dose  of  tuberculin  should  be  administered  and 
that  a  reaction  should  be  considered  to  have  occurred  only  when  the 
temperature  remained  elevated  for  several  hours. 

Many  of  the  supposed  errors  of  diagnosis  made  from  the  tuberculin 
tests  during  the  first  years  of  its  use  were  due  to  an  insufficient  search 
for  the  tuberculous  lesion  in  the  carcass  of  the  slaughtered  animal. 
Tuberculin  proved  to  be  a  much  more  delicate  test  for  the  existence  of 
tuberculosis  in  cattle  than  was  at  first  appreciated,  and  it  was  not  until 
the  veterinarians  learned  that  a  single  small  tubercle  in  an  obscure 
part  of  the  body  was  enough  to  cause  a  reaction  that  they  began  making 
a  sufficiently  careful  search  to  discover  such  a  lesion  in  case  of  its  exist- 
ence. It  is  now  generally  admitted  that  a  reaction  seldom,  if  ever, 


48  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

occurs  without  there  being  a  tubercle  somewhere  in  the  animal's  body. 
The  errors  of  diagnosis  arise  not  with  the  animals  which  react,  but 
with  the  tuberculous  animals  which  fail  to  show  a  reaction.  Nearly 
all  the  animals  failing  to  react  although  affected  with  tuberculosis  may 
be  grouped  in  two  classes.  The  first  of  these  classes  consists  of  ani- 
mals in  an  advanced  stage  of  the  disease  and  in  most  of  which  the  dis- 
ease may  be  recognized  by  physical  examination.  The  second  class 
consists  of  animals  which  have  been  injected  with  tuberculin  one  or 
more  times  and  which  have  become  insensible  to  it. 

Tuberculin  is  of  inestimable  value  for  ascertaining  whether  tuber- 
culosis exists  in  a  herd  of  cattle  at  a  period  when  it  could  not  possibly 
be  diagnosed  by  physical  examination.  For  this  purpose  it  is  practi- 
cally infallible  in  its  indications,  since  when  the  disease  exists  in  a 
herd  of  any  size  some  of  the  affected  animals  are  certain  to  show  a 
reaction.  There  are  very  many  cases  on  record  where  herds  supposed 
by  their  owners  to  be  free  from  disease  were  found  by  the  tuberculin 
test  to  be  seriousl}7  infected.  The  determination  of  the  fact  of  the 
existence  of  tuberculosis  in  a  herd  is  of  the  greatest  importance,  for 
it  enables  the  owner  to  adopt  at  the  earliest  moment  the  measures 
which  are  needed  for  the  control  and  eradication  of  the  contagion. 
The  animals  which  react  to  the  test  are  certainly  affected,  and  those  in 
the  same  herd  which  fail  to  react  must  be  regarded  as  suspicious  until 
they  have  been  kept  for  several  months  after  the  last  reacting  animal 
has  been  removed  and  have  undergone  subsequent  tests  without 
reacting. 

The  cows  in  a  tuberculous  herd  which  failed  to  react  to  the  tuber- 
culin test  should  be  submitted  to  careful  physical  examination,  and 
those  which  are  emaciated,  or  have  abnormal  sounds  in  their  lungs,  or 
are  frequently  in  heat,  or  which  cough  or  have  digestive  disturbances, 
should  be  regarded  as  probably  affected.  The  udder  should  also  be 
examined  with  great  care,  and  if  hard,  painless  swellings  are  found  in 
one  or  more  quarters,  and  particularly  if  a  hind  quarter  is  affected, 
the  trouble  is  probably  caused  by  the  tuberculosis  bacillus.  By  this 
careful  physical  examination  the  cows  in  a  more  or  less  advanced  stage 
of  the  disease  which  fail  to  react  to  the  tuberculin  test  may  be  detected 
and  measures  taken  to  prevent  the  disease  spreading  from  them. 

The  second  class  of  cases  from  which  errors  are  liable  to  occur — that 
is,  the  animals  which  have  been  injected  with  tuberculin  'until  they 
have  lost  their  sensitiveness  to  it — are  not  likely  to  be  found  in  a  herd 
tested  for  the  first  time,  unless  new  animals  have  recently  been  pur- 
chased. The  first  test  of  a  herd  with  tuberculin  combined  with  a 
physical  examination  of  the  individual  animals  may  therefore  be 
accepted  as  reliable  in  its  indications,  not  only  as  to  the  existence  of 
tuberculosis  in  the  herd,  but  also  as  to  the  healthf  ulness  of  the  various 
animals  composing  the  herd. 

With  newly  purchased  animals  and  those  about  to  be  taken  into  the 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  49 

herd  the  case  is  different.  A  tuberculous  animal  may  have  been  injected 
several  times  for  the  express  purpose  of  putting  it  into  a  condition  that 
will  prevent  its  reacting  at  the  time  of  sale,  or  it  may  have  been 
injected  a  number  of  times  in  the  ordinary  course  of  procedure  with  a 
tuberculous  herd.  It  is,  therefore,  unsafe  to  purchase  an  animal  from 
a  tuberculous  herd,  even  if  it  fails  to  react  when  tested  with  tuberculin. 
A  single  injection  with  tuberculin  may  be  sufficient  to  prevent  an 
animal  from  reacting  until  a  period  of  five  or  six  months,  or  longer, 
has  elapsed  after  the  test  was  made;  on  the  other  hand,  some  animals 
react  to  every  injection  of  tuberculin,  even  when  there  are  but  a  few 
weeks'  interval. 

The  results  of  the  test  and  examination  of  the  extensively  diseased 
herd  of  the  Soldiers'  Home,  at  Washington,  by  the  Bureau  of  Animal 
Industry,  are  of  especial  interest  because  of  the  great  care  which  was 
exercised  to  secure  accuracy.  In  this  herd  60  animals  were  tested 
with  tuberculin  and  all  of  them  were  afterwards  slaughtered  and  thor- 
oughly examined.  The  number  of  animals  in  the  herd  which  reacted 
was  49,  and  the  number  which  failed  to  react  was  11.  There  was  only 
1  animal  among  those  which  reacted  in  which  no  tuberculous  lesions 
were  found.  Of  the  11  animals  which  failed  to  react,  however,  there 
were  5  that  were  found  to  be  diseased.  One  of  these  which  proved  to 
have  extensive  tuberculosis  had  a  high  temperature  (103.6°  F.)  the 
day  before  the  test.  This  high  temperature  was  sufficient  reason  for 
considering  that  the  cow  was  probably  tuberculous,  and,  moreover, 
the  disease  had  been  recognized  from  the  external  appearance  of  the 
animal  and  she  had  already  been  isolated  from  the  herd.  In  the  four 
remaining  animals  which  were*  diseased  but  failed  to  react,  the  lesions 
were  small  and  could  not  be  detected  by  physical  examination.  This 
is  an  unusual  proportion  of  such  cases.  The  disease  in  three  of  these 
cows  was  apparently  stationary,  as  the  nodules  were  small  and  cal- 
careous. In  the  fourth  cow  the  lesions  were  also  small,  and  so  far  as 
could  be  determined  were  confined  to  the  glands. 

In  the  carefully  compiled  statistics  published  by  Voges37  in  1897  it 
was  shown  that  of  7,327  animals  tested,  and  of  which  the  accuracy  of 
the  tests  was  determined  by  post  mortem  examinations,  there  were  but 
204  errors  of  diagnosis,  or  2.78  per  cent.  Pearson2  states  that  in  the 
work  of  the  State  live  stock  sanitary  board  of  Penns^vlvania  post-mortem 
examinations  were  made  on  about  4,400  cattle  which  had  reacted  to  the 
tuberculin  test,  and  that  among  all  these  animals  there  were  but  8  in 
which  no  lesions  of  tuberculosis  were  found.  He  adds  with  reference  to 
these  that  we  are  not  justified  in  saN'ing  that  tubercular  lesions  did  not 
exist,  for  the  reason  that  every  portion  of  the  carcass  could  not  be 
examined;  but  it  could  only  be  said  that  they  were  not  found. 

That  cattle  which  once  react  to  the  tuberculin  test  may  fail  to  react 
on  subsequent  tests  is  a  fact  which  should  be  borne  in  mind.  Obser- 
1881— No.  38—06 1 


50 


TUBERCULOSIS    OK   THE    FOOD-PRODUCING    ANIMALS. 


rations  relative  to  this  behavior  of  the  animal  body  toward  tuberculin 
have  been  made  by  many  investigators.  Some  tests  made  at  the  Storrs 
Experiment  Station  are  interesting  examples  of  the  failure  of  tubercu- 
lin under  such  conditions. 

The  following  table  shows  the  record  made  at  the  Storrs  station  in 
retesting  cows  belonging  to  the  herd  of  the  Connecticut  Agricultural 
College:25 

Failure  of  tuberculin  in  case  of  repeated  injections. 


Number  of  animal. 

Number 
(if  tests 
previous 
to  first 
response. 

Date  of  first  response. 

Date  of  test  after  first 
response. 

Date  of  second 
test  after  first 
response. 

1  .. 

1 

December,  1898  

May,  1899  a... 

3  

2 

...do... 

do.  b  

4  

1 

...do... 

do."  

April,  1900  a 

6       ..               

1 

..  ..do  

..  ..do.  a 

Do  & 

6  

3 

December,  1899  

April,  1900a  

7  

2 

December,  1898  .  .  . 

May,  1899  *>  

8                             ...  . 

0 

.  do  

do.  o 

Do  o 

9  

1 

.  ...do  

.  ..  do.  6 

Do  ft 

10  

3 

December,  1  899  

April,  1900«  

11  

2 

May,  1899  

November,  1900  &  

12  

3 

April,  1900  

do.6  

14  

1 

December,  1898  

May  1899  a  

15  

3 

...do... 

do.  b  

16 

3 

do 

do  <t 

17  

....do... 

...do.&... 

18  

2 

do  

do.b  

Total  

28 

lef'i 

4^ 

^«8 

\<i2 

a  Failed  to  react. 


Reacted. 


This  table  shows  that  16  animals  reacted,  and  that  all  but  2  of  these 
had  previously  been  injected  from  one  to  three  times.  From  six 
months  to  a  year  after  this  first  reaction  these  16  animals  were  again 
injected,  when  8  responded  and  8  failed  to  respond.  When  eleven 
months  more  had  elapsed  4  of  these  animals  were  tested  for  the  second 
time  after  their  first  response,  and  of  these  2  reacted  and  2  failed  to 
react.  There  were,  therefore.  10  reactions  and  10  failures  to  react  to 
injections  subsequent  to  the  first  reaction,  or  50  per  cent  of  failures. 

Phelps,24  of  the  same  station,  gives  the  following  statement  of  the 
repeated  testing  of  4  tuberculous  cows,  taken  for  experimental  pur- 
poses, during  the  four  years  they  were  kept  at  the  station. 

January  26-27,  1897,  first  tuberculin  test  (at  station),  all  reacted. 

April  26-27,  1897,  second  tuberculin  test  Nos.  1341  and  1344  reacted. 

July  30-31,  1897,  third -tuberculin  test,  none  of  the  cows  react  i-<l. 

September  27-28,  1897,  fourth  tuberculin  test,  none  of  the  cows  reacted. 

December  17-18,  1897,  fifth  tuberculin  test,  No.  1344  reacted. 

April  11-12,  1898,  sixth  tuberculin  test,  No.  1343  reacted. 

December  22-23,  1898,  seventh  tuberculin  test,  none  of  the  cows  reacted. 

June  2-3,  1899,  eighth  tuberculin  test,  No.  1343  reacted. 

December  1-2,  1899,  ninth  tuberculin  test,  No.  1341  reacted. 

March  19-20,  1900,  tenth  tuberculin  test,  none  of  the  cows  reacted. 

September  28-29,  1900,  eleventh  tuberculin  test,  No.  1341  reacted. 

These  cows,  Nos.  1337,  1341,  1343,  and  1344,  had  been  tested  before  they  came  to 
the  station  by  the  State  cattle  commissioners,  first  in  March,  1896,  when  none  of 
them  reacted  and  they  were  pronounced  healthy,  and  they  probably  were  free  from 
tuberculosis  at  that  time;  and  second  in  October,  1896,  when  they  reacted  and  were 
condemned  as  tuberculous. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  51 

It  was  said  by  Regner21  at  the  International  Veterinary  Congress 
held  in  Budapest  in  1905  that  tuberculin  is  an  invaluable  and  indispen- 
sable means  for  the  extirpation  of  tuberculosis,  but  he  who  relies 
exclusively  upon  it  for  differentiating  between  tuberculous  and  non- 
tuberculous  animals  will  sooner  or  later  have  bitter  cause  to  regret  it. 
Not  only  tuberculosis  permitting  of  clinical  diagnosis,  but  also  cases 
where  tuberculosis  is  present  in  a  decided  but  not  very  high  degree, 
usually  not  easily  to  be  detected,  may  with  individual  animals  elude  the 
tuberculin  test,  and  in  a  relatively  short  time,  under  favorable  circum- 
stances, commit  fearful  ravages  among  the  stock  found  free  from  reac- 
tion. Professor  Svenssen,  of  Stockholm,  has  also  proved  by  means  of 
a  long  series  of  experiments  that  tuberculin  is  somewhat  uncertain  for 
repeated  tests  upon  animals  once  found  to  react.  These  facts  render 
a  clinical  and  bacterioscopic  diagnosis  imperatively  necessary.  Sup- 
pressive  measures  must  especially  be  directed  against  the  lung  tuber- 
culosis, which  is  the  most  important  factor  of  the  dissemination  of  the 
pest  among  the  cattle  stalls. 

Taking  into  account  recent  publications  on  the  subject,  Eber38 
formulates  the  following  principles  for  judging  the  tuberculin  reaction 
with  cattle,  which  are  based  upon  numerous  observations  of  his  own 
relative  to  the  normal  body  temperature  of  cattle  and  its  variations: 

.1.  For  young  cattle  up  to  6  months  old. — With  young  cattle  up  to  6  months  old,  if 
the  temperature  before  the  tuberculin  injection  is  not  found  to  exceed  40°  C.  ( 104°  F.) , 
all  rises  in  temperature  above  40°  C.  (104°  F. )  are  to  be  looked  upon  as  reactions, 
provided  that  the  difference  between  the  highest  temperature  observed  before  the 
injection  and  the  highest  observed  after  it  is  at  leant  0.5°  C.  (0.9°  F. ). 

B.  For. cattle  more  than  6  months  old. — 1.  Only  such  cattle  are  to  be  submitted  to  the 
tuberculin  test  as  have  a  temperature  not  exceeding  39.5°  C.  (103.1°  F. )  at  the  time 
of  the  injection. 

2.  A  rise  of  temperature  to  39.5°  C.  (103.1°  F.)  after  the  tuberculin  injection  is  not 
in  any  case  to  be  regarded  as  suspicious. 

3.  With  all  cattle  having  temperatures  not  exceeding  39.5°  C.  (103.1°  F. )  at  the 
time  of  the  tuberculin  injection,  every  rise  above  40°  C.  (104°  F. )  is  to  be  regarded 
as  a  reaction. 

4.  Further,  all  rises  of  temperature  above  39.5°  C.  (103.1°  F.)  to  40°  C.  (104°  F.) 
are  to  be  considered  reactions,  when  the  total  rise  compared  with  the  temperature 
before  the  injection  is  at  least  1°  C.  (1.8°  F. ). 

5.  All  rises  of  temperature  above  39.5°  C.  (103.1°  F. )  to  40°  C.  (104°  F.) ,  when  the 
total  rise,  compared  with  the  temperature  before  the  injection,  is  less  than  1°  C. 
(1.8°  F. ),  should  be  regarded  as  doubtful,  and  the  case  judged  on  its  merits. 

The  decision  as  to  which  of  these  cases  are  to  be  considered  as  reactions  and  which 
as  nonsuspicious  is  to  be  made  according  to  the  nature  of  the  case.  It  has  been 
found  by  experience  that  important  aids  to  forming  a  decision  are  furnished  by  the 
total  increase  compared  with  the  temperature  before  the  injection — which  with 
reacting  animals  as  a  rule  should  be  0.5°  C.  (0.9°  F. )  at  least — by  the  character  of 
the  temperature  curve,  and  by  an  exact  clinical  examination,  the  necessity  for  which 
in  doubtful  cases  is  again  emphasi/.ed. 

6.  For  all  those  cases  in  which  the  tuberculin  test  is  simply  to  serve  as  a  means  of 
ascertaining  the  dissemination  of  tuberculosis  in  a  stock  of  cattle,  with  the  object  of 
separating  the  suspected  animals  from  those  which  are  not  suspected,  so  as  to  carry 
on  the  suppression  of  tuberculosis,  it  is  sufficient,  according  to  Ostertag,  to  regard 
all  those  cattle  as  suspected  the  interior  body  temperature  of  which  exceeds  39.5°  C. 
(103.1°  F. )  after  injection  of  the  prescribed  quantity  of  tuberculin — that  l>eing  an 
increase  of  at  least  0.5°  C.  (0.9°  F.)  above  the  highest  temperature  observed  before 
the  injection. 


52  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

It  has  often  been  alleged,  generally  by  persons  who  have  had  no 
great  amount  of  experience  in  its  use,  that  tuberculin  has  an  injurious 
effect  upon  the  animals  into  which  it  is  injected.  This  is  contrary  to 
the  almost  unanimous  opinion  of  the  scientific  men  who  have  studied 
its  effects  and  who  have  had  most  experience  in  testing  cattle  with  it. 
Tuberculin  has  little  or  no  effect  upon  healthy  cattle  and  its  action 
upon  tuberculous  cattle  is  not  serious.  The  writer  has  elsewhere  f) 
collected  the  opinions  of  many  experts  upon  this  subject  and  would 
refer  to  that  article  for  details  which  can  not  be  given  here. 

A  careful  study  of  a  great  mass  of  literature  on  the  subject  has  led 
to  the  conclusions  which  follow: 

1.  The  tuberculin  test  for  tuberculosis  is  wonderfully  accurate  in 
its  results,  and  if  an  animal  responds  it  is  certainly  affected  with  the 
disease. 

2.  The  reaction  to  tuberculin  is  no  indication  of  the  extent  of  the 
disease   in   the  reacting   animal,   and   there  is   frequently  a  greater 
reaction  in  an  animal  with  slight  lesions  than  in  another  in  which  the 
disease  is  very  much  more  advanced. 

3.  A  small  percentage  of  the  cattle  affected  with  tuberculosis  fail 
for  some  reason  to  react  to  the  tuberculin  test. 

4:.  Tuberculin  in  the  doses  used  for  making  the  test  has  no  injurious 
effect  upon  healthy  cattle;  if  it  has  any  effect  at  all  it  slightly  increases 
their  power  to  resist  the  tuberculosis  infection. 

5.  The  effect  of  tuberculin  upon  cattle  alreadj'  suffering  from  tuber- 
culosis is  to  cause  a  temporary  fever  with  an  increase  of  temperature 
of  from  2°  to  7°  F.,  which  usually  lasts  not  longer  than  twenty-four 
hours.  It  is  doubtful  if  tuberculin  in  this  dose  ever  aggravates  the 
tuberculous  process  in  cattle,  and  there  is  some  evidence  that  it  may 
have  a  favorable  effect. 

Tuberculin  is  not  much  used  as  a  test  for  tuberculosis  in  the  smaller 
animals,  such  as  swine,™  sheep,  and  poultry,  because  the  normal  varia- 
tion of  temperature  in  these  animals  is  so  great  that  it  is  difficult  to 
arrive  at  any  accurate  conclusions  as  to  whether  a  reaction  has  occurred. 

EXAMINATION   OF   THE   CARCASS. 

The  carcasses  of  all  animals  which  die  or  are  slaughtered  from  a  herd 
should  be  carefully  examined  to  determine  whether  they  are  affected 
with  tuberculosis.  This  is  an  important  means  of  learning  as  to  the 
existence  of  the  disease,  and  may  give  an  early  warning  when  its  pres- 
ence has  not  been  suspected.  The  examination  of  carcasses  is  espe- 
cially necessary  with  swine,  since  the  tuberculin  test  is  not  generally 
used  and  is  rather  unsatisfactory  with  these  animals.  An  examination 

a  Experiments  recently  made  by  the  Bureau  of  Animal  Industry  in  testing  hogs 
with  tuberculin  indicate  that  the  application  of  the  test  to  these  animals  is  practi- 
cable, and  that  the  results  are  as  reliable  as  with  cattle,  provided  the  hogs  are  kept 
very  quiet  for  some  time  before  and  throughout  the  test. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  53 

of  the  carcasses  of  all  animals  from  a  herd  is  an  easy  and  accurate  way 
of  keeping  informed  as  to  the  condition  of  health  of  that  herd,  and 
particularly  as  to  the  existence  of  any  form  of  infection,  or  of  any 
injurious  parasites. 

The  examination  of  a  carcass  for  tuberculosis  must  not  stop  with  an 
inspection  of  the  lungs.  The  bronchial  and  mediastinal  lymphatic 
glands,  which  lie  near  the  entrance  of  the  bronchi  into  the  lungs  and 
along  the  course  of  the  esophagus  between  the  lungs,  are  more  fre- 
quently affected  than  the  lungs  themselves.  Of  primary  importance 
with  swine  are  the  glands  of  the  neck,  which  are  affected  in  a  large 
proportion  of  the  cases.  In  cattle  the  retropharyngeal,  mesenteric, 
and  portal  glands  should  certainly  be  examined,  as  well  as  the  liver, 
kidneys,  and  spleen.  If  the  examination  is  made  by  a  veterinarian, 
all  of  the  accessible  organs  should  be  inspected.  The  yellowish  nodules 
are  easily  seen  in  the  principal  organs  of  the  body,  and  are  also 
unmistakable  in  the  lymphatic  glands  if  these  bodies  are  opened  with 
the  knife.  Any  farmer  or  dairyman  should  with  a  little  practice  be 
able  to  recognize  tubercular  lesions  in  most  cases,  or  should  at  least  be 
able  to  tell  if  there  is  any  thing  having  the  general  appearance  of  tuber- 
culosis, and  in  case  of  doubt  the  affected  organ  may  be  saved  and 
taken  to  a  veterinarian  for  an  expert  opinion. 

IMMUNIZATION  OF  CATTLE  AGAINST  TUBERCULOSIS. 

The  immunization  of  cattle  against  tuberculosis  is  a  subject  upon 
which  investigators  have  been  working  for  a  number  of  }-ears,  with 
results  that  have  inspired  the  hope  that  we  shall  have  in  the  near 
future  an  additional  means  of  combating  the  disease,  and  one  that  will 
greatly  strengthen  our  present  resources.  The  papers  which  have 
recently  been  published  on  this  method  of  prevention,  together  with 
the  discussions  at  the  International  Veterinary  Congress  held  in  Buda- 
pest in  1905,  show  that  the  ablest  veterinarians  in  the  world  are  confi- 
dently expecting  that  a  practical  and  safe  plan  of  procedure  will  soon 
be  developed.  If  this  expectation  is  fulfilled  the  operations  against 
tuberculosis  will  not  only  be  materially  simplified,  but  the  expense 
involved  in  the  eradication  of  the  disease  and  the  loss  falling  upon  the 
individual  owners  will  be  vastty  reduced. 

A  method  of  prevention  which  promises  so  much  is  deserving  of 
very  careful  consideration,  even  at  this  early  stage  of  its  development, 
for  undoubtedly  we  shall  soon  be  called  upon  to  pass  judgment  as  to 
its  practicability.  If  it  can  be  safely  applied  and  is  effective,  it  should 
bo  adopted  and  utilized  as  soon  as  it  is  perfected;  but  if,  on  the  other 
hand,  it  is  neither  safe  nor  a  satisfactoiy  preventive,  these  facts  should 
be  made  known  as  soon  as  possible.  The  value  of  the  method  can 
only  be  estimated  when  we  have  some  knowledge  of  the  investigations 
which  have  led  up  to  it,  and  when  we  fully  understand  and  appreciate 
the  dangers  which  must  be  avoided. 


54  TUKRBCULOSIS    OF    THE    FooD-PKoDlTCINO    ANIMALS. 

EARLY    EXPERIMENTS. 

As  long  ago  as  1889  Da  re  m  berg41  made  experiments  with  a  view  to 
the  production  of  immunity  from  tuberculosis  by  inoculating  guinea 
pigs  and  rabbits  with  sterilized  cultures  of  the  tubercle  bacillus.  The 
guinea  pigs  died  and  the  rabbits  were  made  sick;  but  some  of  the  rab- 
bits after  recovery  and  upon  inoculation  with  virulent  tuberculosis 
germs  showed  considerable  resistance  to  the  disease,  as  compared  with 
similar  animals  which  had  not  received  the  preventive  treatment. 
This  investigator  also  made  experiments  to  test  the  effect  of  small 
doses  of  virus',  and  in  one  series  of  experiments  he  used  medullas  as 
a  vaccinating  material.  His  results,  in  some  respects,  were  very 
striking,  and  appear  to  have  made  a  profound  impression  upon  him, 
for  his  paper  which  gave  an  account  of  the  investigations  was  con- 
cluded with  these  words: 

From  all  these  facts  it  follows  that  tuberculous  virus  is  a  poison  which  can  be 
treated  in  a  like  manner  with  mineral  or  organic  poisons.  Its  toxicity  may  In- 
increased  or  diminished  almost  at  will.  On  the  other  hand,  one  may  augment  the 
resistance  of  the  organism  against  its  disorganizing  action.  And  I  firmly  believe 
that  the  day  will  come  when  in  this  gamut  of  diverse  virulences  will  be  found  the  cor- 
rect note  which  will  transform  the  virus  into  vaccine,  which  will  fix  wjth  precision 
the  attenuation  infallibly  conferring  immunity. 

At  the  time  this  was  written  it  seemed  that  the  author  wras  too  san- 
guine and  there  were  few  who  believed  it  possible  to  vaccinate  success- 
fully against  a  disease  which  ran  so  slow  a  course  and  which  was  fatal 
in  so  large  a  proportion  of  cases.  If  immunity  were  developed  in  the 
animal  body  by  the  multiplication  of  the  tuberculosis  germs,  why  did 
not  this  immunity  show  itself  during  the  progress  of  the  nattiralh' 
acquired  disease,  thus  making  it  a  disease  of  limited  duration,  ending 
in  recovery?  It  appeared  incredible  that  a  bacillus  which  in  so  many 
cases  advances  slowly  and  insidiously  from  one  part  of  the  animal 
body  to  another,  often  consuming  years  in  its  development  to  a  degree 
where  the  life  of  the  animal  is  destroyed,  should  by  its  normal  biological 
processes  confer  a  power  of  resistance  upon  the  tissues  of  that  animal 
body  which  would  be  effective  against  itself. 

In  the  same  year  Grancher  and  Martin*2  made  public  the  results  of 
a  series  of  researches  of  great  interest  in  this  connection  because  they 
demonstrated  that  at  that  early  date  they  had  discovered  a  reliable 
method  of  attenuating  the  tubercle  bacillus.  These  authors  say  that 
they  had  applied  themselves  to  the  task  of  obtaining  graduated  viru- 
lences, even  to  the  loss  of  virulence  in  the  bacillus,  and  although  the 
scale  was  in  nowise  mathematical  it  was  sufficient  to  be  utilized  in 
about  the  same  manner  as  were  the  dried  marrows  used  in  the  method 
of  Pasteur  for  the  treatment  of  rabies.  The}'  designated  under  the 
name  of  virulence  No.  1  the  most  virulent  cultures  in  their  series. 
which  killed  rabbits  by  intravenous  injection  in  fifteen  days  or  one 
month.  Virulences  Nos.  2y  3,  4,  5,  6,  7,  8,  9,  and  10  were  successively 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  55 

decreasing.  The  cultures  from  No.  10  to  No.  7,  inclusive,  resown  in 
the  culture  apparatus,  no  longer  developed,  and  were  without  effect 
upon  rabbits.  Virulences  Nos.  2  and  3  were  fatal,  but  at  varying  peri- 
ods according  to  the  resistance  of  the  animal.  They  believed  that  they 
had  succeeded  in  giving  to  rabbits  the  power  of  a  prolonged  resist- 
ance against  the  most  rapid  and  the  most  certain  experimental  tuber- 
culosis, and  that  they  had  also  succeeded  in  conferring  upon  these 
animals  an  immunity  against  this  same  disease,  the  duration  of  which 
remained  to  be  determined. 

Late  in  the  year  1890  Trudeau43  contributed  a  paper  to  the  Medical 
Record  in  which  he  gave  details  of  two  series  of  experiments  made 
with  a  view  of  obtaining  immunity.  In  the  first  series  preventive 
inoculation  with  the  nonliving  chemical  products  of  the  life  processes 
of  the  tubercle  bacillus  failed  to  afford  any  protection  against  subse- 
quent infection  with  virulent  living  tubercle  bacilli.  In  the  second 
series  preventive  inoculation  with  an  attenuated  living  germ,  which 
was  capable  of  producing  in  most  cases  only  an  indolent  and  localized 
tubercular  process  at  the  site  of  injection,  failed  to  protect  against 
subsequent  inoculation  with  virulent  tubercle  bacilli. 

In  May,  1894,  Trudeau 4t  read  a  paper  before  the  Association  of 
American  Physicians  on  the  production  of  immunity  with  avian  bacilli. 
He  concluded  that  rabbits  which  survived  the  subcutaneous  inocula- 
tion of  living  cultures  of  the  avian  tubercle  bacillus  of  gradually 
increasing  virulence  and  in  graded  doses  undoubtedly  acquired  a  cer- 
tain degree  of  immunity  against  subsequent  eye  inoculation  with  the 
mammalian  cultures,  which  immunity  had  in  some  animals  under  his 
observation  persisted  for  over  a  year  without  the  slightest  evidence 
of  a  relapse.  He  also  found  that  while  the  rabbit,  which  is  very  much 
more  susceptible  to  the  avian  than  to  the  mammalian  bacillus,  may 
acquire  a  certain  degree  of  immunity  against  the  latter  by  preventive 
inoculations  of  the  former,  the  guinea  pig,  which  can  rarely  and  with 
great  difficulty  be  killed  by  the  avian  microbe,  is  in  no  way  protected 
by  this  treatment. 

In  December,  189-i,  De  Schweinitz45  published  an  article  entitled 
"The  Attenuated  Bacillus  Tuberculosis;  Its  Use  in  Producing  Immu- 
nity to  Tuberculosis  in  Guinea  Pigs."  In  this  article  he  gave  the  re- 
sults of  certain  observations  and  experiments  made  by  him  in  his  work 
for  the  Bureau  of  Animal  Industry,  which  were,  briefly,  as  follows: 

It  was  noticed  by  him  that  a  strain  of  tubercle  bacilli  which  had  been  grown  on 
glycerin  agar  and  in  glycerin  beef  broth  for  fourteen  generations  no  longer  destroyed 
guinea  pigs  as  readily  as  it  had  previously  done.  In  the  case  of  the  fourteenth  gen- 
eration it  required  six  months  before  the  disease  developed.  He  consequently  inocu- 
lated a  number  of  guinea  pigs  with  the  seventeenth,  eighteenth,  nineteenth,  and 
twentieth  generations  of  this  germ.  After  some  months  the  guinea  pigs  that  had 
been  inoculated  with  the  attenuated  germ  remained  quite  well,  and  one  which  was 
chloroformed  proved  on  examination  to  be  free  from  disease.  In  order  to  test  the 
immunity  of  these  animals  4  guinea  pigs  which  had  been  inoculated  with  the  attenu- 
ated germ  and  4  check  guinea  pigs  which  had  received  no  treatment  were  all  inocu- 
lated with  material  obtained  from  a  tubercular  cow  which  had  just  been  killed. 


56  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

After  seven  weeks  the  checks  were  all  found  dead  from  tuberculosis,  while  the  treated 
animals  all  appeared  perfectly  well.  One  of  these  was  then  chloroformed  and  care- 
fully examined,  but  no  trace  of  the  disease  could  be  detected.  Even  the  local  lesion 
that  was  produced  where  the  material  had  been  injected  had  entirely  healed.  He 
fed  these  attenuated  bacilli  to  a  calf  and  injected  them  intravenously  into  a  cow  with- 
out any  disease  being  produced. 

He  concluded  from  these  experiments  that  "our  attenuated  germ 
may  possibly  prove  very  valuable  in  checking  or  controlling  tubercu- 
losis in  animals,  especially  cattle." 

The  investigation  of  this  attenuated  tuberculosis  bacillus  was  con- 
tinued by  De  Schweinitz  and  Schroeder,*6  who  in  1896  stated  that  their 
experiments  showed  conclusively  that  from  an  original!}7  virulent 
germ  they  had  succeeded  in  obtaining  an  attenuated  germ  which  even 
in  large  doses  was  apparentl}'  harmless  to  guinea  pigs,  rabbits,  cattle, 
horses,  and  monkeys.  They  had  inoculated  cows  and  calves  with  this 
germ  in  doses  varying  from  2  c.  c.  to  500  c.  c.  at  a  time  without  the 
production  of  tuberculosis. 

The  history  of  one  of  the  animals  in  the  experiments  of  De  Schwei- 
nitz and  Schroeder*7  is  very  interesting,  since  it  clearly  indicates  the 
possibility  of  immunizing  cattle  against  tuberculosis. 

A  cow  which  had  been  previously  tested  with  tuberculin  received  on  July  26, 1894, 
an  intravenous  injection  of  16  c.  c.  of  an  attenuated  cultureof  the  human  tubercle  bacil- 
lus. Tested  November  19,  no  reaction  to  tuberculin  was  noted.  On  November  28,  6  c.  c. 
of  an  attenuated  culture  was  injected  into  the  abdominal  cavity.  The  injections  were 
repeated  at  various  times,  the  animal  being  kept  in  the  experiment  for  twenty-eight 
months  and  receiving  altogether  20,870  c.  c.  of  culture,  of  which  as  large  an  amount 
as  2,000  c.  c.  was  given  at  one  time.  On  February  22,  1898,  this  animal  received  an 
injection  of  virulent  material  taken  from  a  cow  affected  with  generalized  tuberculosis. 
The  injection  was  made  into  the  thoracic  cavity.  The  cow  thus  treated  wa.s  killed 
September  20,  1898,  and  a  careful  autopsy,  made  by  Doctor  Schroeder,  failed  to  dis- 
close the  slightest  evidence  of  tuberculosis. 

These  experiments  of  De  Schweinitz  and  Schroeder  are  in  the  nature 
of  pioneer  work  for  the  immunization  of  cattle  against  tuberculosis. 
It  is  evident  that  they  succeeded  in  obtaining  attenuated  tubercle 
bacilli  which  could  be  inoculated  into  guinea  pigs  and  cattle  without 
producing  any  disease.  It  is  also  evident  that  they  produced  immunity 
in  guinea  pigs  b^v  inoculating  them  with  this  attenuated  material,  since 
four  of  these  pigs  resisted  perfectly  inoculation  with  virulent  bovine 
bacilli  which  killed  all  the  checks  in  seven  weeks.  And,  finally,  it 
seems  evident  that  they  produced  immunity  in  a  cow,  since  this  animal 
was  able  to  resist  an  intrathoracic  injection  of  active  bovine  tubercu- 
losis virus;  and  not  only  did  she  show  no  symptoms  of  disease  while 
living,  but  a  careful  post-mortem  examination  failed  to  reveal  the 
slightest  lesion  of  the  disease  at  the  point  of  inoculation  or  elsewhere. 
M'FADY  BAN'S  EXPERIMENTS. 

McFadyean  *8  published  some  interesting  experiments  in  1901  which 
seemed  to  show  that  the  animals  used  in  his  experiments  had  acquired 
a  high  degree  of  immunity. 

The  first  animal  was  a  yearling  heifer  which  received  9  doses  of  tuberculin  of 
1  c.  c.  each,  with  intervals  of  three  to  eleven  days.  It  was  then  given  3  doses  of 
10  c.  c.  each,  and  following  this  6  doses  of  20  c.  c.  each.  Thirteen  days  after  the  last 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  57 

dose  of  tuberculin  was  given  this  animal  received  an  intravenous  injection  of  2  c.  c. 
of  a  liquid  very  rich  in  tubercle  bacilli,  prepared  by  rubbing  up  some  caseopurulent 
matter  from  the  mesenteric  gland  of  a  horse  with  sterile  water.  On  the  same  day 
(February  6,  1900)  two  other  animals  of  about  the  same  size  and  age  were  infected 
in  the  same  way  with  a  like  quantity  of  the  same  material.  These  two  animals, 
which  may  be  regarded  as  checks,  subsequently  became  ill,  and  when  they  were 
killed  on  the  10th  of  April  their  lungs  were  found  to  contain  numerous  tubercles, 
while  the  bronchial  and  mediastinal  lymphatic  glands  were  greatly  enlarged  and 
caseating.  The  first  animal  mentioned  had  reacted  to  the  first,  second,  fourth,  and 
sixth  doses  of  tuberculin,  and  then  failed  to  respond  even  to  the  large  doses  until 
after  it  received  the  infecting  material,  when  it  responded  twice  to  doses  of  1  c.  c. 
Later  it  was  treated  with  tuberculin  in  doses  varying  from  5  c.  c.  to  20  c.  c.  without 
any  important  rise  of  temperature  occurring. 

On  May  22,  1900,  this  animal  was  killed,  and  a  most  searching  post-mortem  exami- 
nation revealed  no  lesion  anywhere  except  in  one  mesenteric  gland,  which  contained 
a  completely  calcified  tubercle  about  the  size  of  a  pea.  The  assumption  was  that 
this  lesion  had  been  in  active  condition  when  the  animal  was  first  tested,  and  that  it 
was  accountable  for  the  reactions  then  obtained.  It  would  appear  that  the  experi- 
menter was  more  or  less  justified  in  concluding  that  this  animal  had  latterly  a  very 
high  degree  of  immunity  against  tuberculosis. 

The  second  animal  was  a  heifer  about  1  \  years  old.  This  heifer  was  tested  with 
tuberculin  on  October  9  and  12  and  November  27,  1899,  and  January  8,  1900, 
reacting  each  time.  The  dose  of  tuberculin  was  1  c.  c.  on  each  occasion.  On  Jan- 
uary 11  the  animal  received  by  intravenous  injection  1J  c.  c.  of  a  liquid  rich  in 
bovine  tubercle  bacilli,  and  another  heifer  was  inoculated  in  the  same  manner  as  a 
control  animal.  The  control  animal  was  killed  on  March  2,  1900,  when  it  was  very 
ill,  and  the  post-mortem  examination  revealed  a  dense  miliary  tuberculosis  of  the 
lungs.  The  experimental  heifer  was  treated  with  tuberculin  as  follows:  January  15, 
17,  21,  and  24,  and  March  8,  20  c.  c.;  March  15,  10  c.  c.,  and  March  28, 20  c.  c.,  with- 
out any  distinct  reaction  occurring.  April  5,  1900,  this  animal  was  again  inoculated 
intravenously  with  2  c.  c.  of  a  liquid  obtained  by  triturating  a  portion  of  the  fresh 
lung  of  a  rabbit,  which  was  dead  as  the  result  of  inoculation  with  bovine  tuber- 
culosis, with  sterile  water.  This  inoculation  did  not  occasion  any  recognizable  dis- 
turbance, but  the  heifer  reacted  when  tested  with  an  ordinary  dose  of  tuberculin 
June  13,  July  18,  and  October  16.  The  test  was  repeated  November  20,  with  an 
indecisive  rise  of  temperature.  November  28  a  third  intravenous  injection  of  tubercle 
bacilli  was  made.  The  dose  was  2  c.  c.  of  a  liquid  obtained  by  triturating  the  tuber- 
cular material  from  the  spleen  of  a  horse  with  sterile  water.  The  animal  was  tested 
with  tuberculin  December  19  and  January  22  following,  and  reacted  each  time. 
January  30,  1901,  the  animal  was  inoculated  for  the  fourth  time  intravenously  with 
5  c.  c.  of  a  rich  emulsion  of  tubercle  bacilli  from  an  artificial  culture  (origin  not 
given).  On  the  day  following  the  injection  the  temperature  had  risen  to  104.2°  F. 
and  remained  at  about  that  point  until  February  4.  Tested  May  15,  it  did  not 
respond.  May  18,  a  fifth  intravenous  inoculation  with  tubercle  bacilli  was  made. 
The  dose  was  5  c.  c.  of  a  rich  emulsion  of  artificial  culture  (origin  not  given).  The 
same  day  the  heifer's  temperature  rose  to  105.6°  F.,  but  it  gradually  fell  and  was 
normal  May  21.  On  June  18,  1901,  the  animal  did  not  respond  to  an  ordinary  dose 
of  tuberculin.  At  the  time  of  reporting,  the  animal  appeared  to  be  in  perfect  health 
and  its  general  condition  was  good. 

The  third  animal  was  a  heifer  about  a  year  old  at  the  time  the  experiment  began. 
It  was  tested  with  tuberculin  May  5,  1899,  without  reacting,  and  was  inoculated 
intravenously  May  10  with  2J  c.  c.  of  an  emulsion  made  from  the  tuberculous  liver 
of  a  pheasant  which  had  contracted  the  disease  naturally.  Between  May  11  and 
October  26  the  animal  was  tested  with  tuberculin  nineteen  times,  reacting  to  the 
third,  fourth,  fifth,  sixth,  seventh,  and  eighth  tests.  November  11  the  animal  was 
inoculated  intravenously  with  2i  c.  c.  of  liquid  containing  tubercle  bacilli  from  the 
liver  of  a  rabbit  which  had  died  after  being  inoculated  with  tubercular  material  from 
a  horse.  Between  November  21  and  January  8  she  was  tested  five  times  with  tuber- 
culin without  reacting.  On  January  11,  1900,  the  animal  received  the  third  intra- 
venous inoculation  with  tubercle  bacilli,  the  dose  being  1J  c.  c.  of  liquid  containing 
bovine  bacilli.  As  in  the  previous  cases,  the  injection  caused  no  obvious  disturbance 
of  the  health.  April  5  a  fourth  intravenous  injection  was  given,  the  material  being 
a  suspension  of  bovine  bacilli  and  the  dose  3  c.  c.  No  symptoms  of  illness  followed 
the  operation,  but  the  animal  reacted  to  some  of  the  subsequent  tests  with  tuberculin. 
On  November  28,  1900,  the  heifer  was  inoculated  intravenously  for  the  fifth  time, 
receiving  2  c.  c.  of  liquid  containing  bacilli  from  the  spleen  of  a  horse.  In  the  tests 
following  this  inoculation  no  rise  of  temperature  occurred.  January  30,  1901,  it  was 
inoculated  intravenously,  this  time  with  5  c.  c.  of  emulsion  from  an  artificial  culture. 


58  TUBERCULOSIS    OF    THE    KO<  U>-I'K<  MMUUNO    ANIMALS. 

On  March  23, 1901,  the  heifer  was  inoculated  intravenously  with  15  c.  c.  and  on  May  18 
with  5  c.  c.  of  an  emulsion  of  a  culture  of  tubercle  bacilli.  At  the  lime  of  reporting, 
the  general  condition  of  the  animal  was  fair  and  it  appeared  to  be  in  good  health. 

The  fourth  animal  was  a  Shorthorn  cow  about  4  years  old.  It  was  tested  with 
tuberculin  and  failed  to  react.  September  29,  1898,  it  was  inoculated  intravenously 
with  4  c.  c.  of  a  suspension  of  tubercle  bacilli  from  the  liver  of  a  fowl.  Following 
this  inoculation  the  cow  reacted  to  the  tuberculin  test.  She  was  afterwards  reinocu- 
lated  intravenously  with  tubercle  bacilli  as  follows:  November  11,  1899,  4  c.  c.  of 
liquid  containing  tubercle  bacilli  from  a  horse;  April  5,  1900,  3  c.  c.  of  a  suspension 
of  bovine  bacilli;  March  23, 1901, 15  c.  c.,  and  May  18,  1901,  5  c.  c.  of  an  emulsion  of 
a  culture  of  tubercle  bacilli.  At  the  time  of  reporting,  this  animal  was  very  fat, 
appeared  to  be  in  perfect  health,  and  did  not  react  to  tuberculin. 

The  report  which  has  just  been  summarized  carries  the  experiment 
up  to  about  July  1,  1901.  At  that  time  the  condition  of  the  three 
animals  remaining  alive  was  such  as  to  lead  to  the  conclusion  that  they 
had  entirely  resisted  the  inoculations  with  virulent  tubercle  bacilli  and 
that  they  were  consequently  immune  to  the  disease.  The  danger  of 
reaching  any  conclusion  in  such  cases  in  the  absence  of  a  post-mortem 
examination  is  strikingly  illustrated  by  the  subsequent  history  of  these 
animals,  for,  although  two  of  them  appeared  to  be  in  "perfect  health'' 
and  the  third  in  "good  health,"  all  three  of  them  died  of  tuberculosis 
within  eight  months  from  the  time  the  report  was  made.  Notwith- 
standing this  unfavorable  termination  of  the  experiment,  its  histoiy 
is  instructive  in  many  respects,  and  particularly  in  showing  the  diffi- 
culty of  immunizing  animals  against  tuberculosis.  It  is  one  of  the 
failures  which  should  be  considered  not  less  than  the  successes. 

The  first  of  these  animals  was  given  a  sixth  inoculation  July  31.  The  material 
employed  was  an  artificial  culture  of  tubercle  bacilli  rubbed  up  with  sterile  water  so 
as  to  form  a  turbid  liquid.  It  was  given  a  seventh  inoculation  October  24  of  10  c.  c. 
of  a  liquid  rich  in  tubercle  bacilli  made  with  the  surface  growth  of  a  culture. 
December  16  the  animal  as  usual  appeared  to  be  quite  well,  but  in  the  early  morn- 
ing of  the  17th  it  was  found  down  in  its  loose  box  and  it  died  almost  immediately. 
The  post-mortem  examination  showed  widely  distributed  lesions  affecting  the  lungs, 
pleura,  kidneys,  omentum,  pia  mater,  and  numerous  glands. 

The  second  animal  received  a  ninth  inoculation  July  21,  1901,  of  5  c.  c.  of  a  rich 
emulsion  of  tubercle  bacilli  from  an  artificial  culture.  A  tenth  inoculation  was  made 
October  5  of  the  surface  growth  of  a  culture  rubbed  up  with  sterile  water,  the  quan- 
tity injected  being  10  c.  c.  October  24  it  was  inoculated  intravenously  for  the 
eleventh  time,  the  dose  being  10  c.  c.  of  emulsion  of  tubercle  bacilli  from  an  artificial 
culture.  This  animal  died  suddenly  and  quite  unexpectedly  December  23,  1901. 
Post-mortem  examination  showed  tubercles  in  the  lungs,  bronchial  and  mediastinal 
glands,  kidneys,  and  pia  mater. 

The  third  animal  received  its  sixth  inoculation  July  31  of  5  c.  c.  of  the  liquid  used 
on  that  date  for  the  preceding  two  cases,  and  the  seventh  inoculation  October  5, 
which  was  also  the  same  as  was  given  to  the  other  animals.  An  eighth  inoculation 
was  given  January  22,  1902,  of  4  c.  c.  of  a  liquid  made  by  rubbing  up  a  quantity  of 
caseous  material  from  the  spleen  of  a  hor.--e  with  sterile  water.  On  the  morning 
of  February  10  it  was  found  that  the  cow  was  unable  to  rise,  and  the  following  morn- 
ing, as  death  appeared  to  be  imminent,  she  was  destroyed  by  chloroform.  The  post- 
mortem examination  showed  tuberculosis  of  the  kidneys,  bronchial  and  mediastinal 
glands,  lungs,  pleura,  tongue,  and  medulla  oblongata.49 

WORK   OF   PEARSON   AND   GILLILAND. 

Important  experiments. were  published  by  Pearson  and  Gilliland50 
in  1902.  One  of  these  experiments  was  conducted  to  determine  the 
immunizing  effect  upon  cattle  of  Koch's  original  tuberculin. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  59 

In  this  experiment  4  cows  were  used.  Two  of  these  cows  were  given  daily  injec- 
tions of  5  c.  c.  of  concentrated  tuberculin  for  ten  days  from  August  24  to  September 
2,  1901.  All  of  the  4  cows  were  fed  daily  100  grams  of  hacked  tuberculous  lung 
tissue  from  a  cow  for  ten  days  from  September  10  to  September  19.  The  2  cows  that 
had  received  the  preliminary  treatment  with  tuberculin  were  each  given  15  c.  c.  of 
concentrated  tuberculin  while  they  were  being  fed  upon  the  tuberculous  material. 

One  of  the  cows  that  had  been  treated  with  tuberculin  and  one  of  those  that  had 
not  been  so  treated  were  killed  November  25,  1901.  The  cow  that  had  been  treated 
with  tuberculin  showed  lesions  of  tuberculosis  in  the  postpharyngeal  and  mesenteric 
lymphatic  glands.  The  control  cow  had  lesions  in  che  right  lung  and  in  the  post- 
pharyngeal, intermaxillary,  bronchial,  mediastinal,  and  mesenteric  lymphatic  glands. 
The  lesions  in  this  control  cow  were  more  widely  distributed  and  more  advanced  than 
in  the  cow  that  had  received  large  quantities  of  tuberculin. 

The  remaining  2  cows  of  the  experiment  were  killed  December  16,  1901.  In  the 
first  of  these  cows  wrhich  had  received  the  injections  of  tuberculin  no  lesions  of  tuber- 
culosis were  found  excepting  in  the  mesenteric  lymphatic  glands.  A  few  of  these 
glands  of  both  the  small  and  large  intestine  showed  small  areas  of  caseation.  The 
second,  or  control,  cow  showed  lesions  of  tuberculosis  in  both  lungs,  in  the  bronchial, 
mediastinal,  and  postpharyngeal  lymphatic  glands,  and  in  the  lymphatic  glands  of 
the  mesentery,  the  last-mentioned  glands  being  more  extensively  involved  than  were 
those  in  the  cow  which  had  received  the  treatment  with  tuberculin. 

The  conclusion  from  this  experiment  wan  that  the  administration  of  the  tuberculin 
had  had  some  effect  in  increasing  the  resistance  of  these  2  cows  to  infection  from 
feeding  tuberculous  material. 

The  next  series  of  experiments  reported  was  made  to  throw  some  light  upon  the 
question  as  to  the  quantity  of  culture  of  tubercle  bacilli  derived  from  human  sputum 
which  might  be  administered  and  the  effect  of  repeated  inoculations  made  in  four 
different  ways,  it  having  been  already  determined  that  such  cultures  were  usually 
comparatively  nonvirulent  for  cattle.  In  these  experiments  there  was  used  a  stand- 
ard suspension  of  tubercle  bacilli  in  water,  made  in  such  proportions  as  to  give  an 
opacity  equal  to  that  of  a  24-hour  culture  of  typhoid  bacilli  in  bouillon,  and  1  c.  c.  of 
such  a  culture  was  estimated  to  contain  the  equivalent  of  0.0013  gram  of  tubercle 
bacilli  dried  ten  days  in  a  desiccating  chamber  over  calcium  chloride. 

The  first  animal  treated  was  a  Jersey  heifer,  shown  by  the  tuberculin  test  to  be  free 
from  tuberculosis.  The  inoculations  of  this  animal  were  as  follows: 

September  29,  1900,  4  c.  c.  intraperitoneally;  March  15,  1901,  13.5  c.  c.  intrave- 
nously; June  1,  1901,  10  c.  c.  intravenously;  August  23,  1901,  20  c.  c.  (5  c.  c.  beneath 
the  skin,  5  c.  c.  into  the  peritoneal  cavity,  5  c.  c.  into  the  jugular  vein,  and  5  c.  c.  into 
the  lung) .  These  injections  were  repeated  with  intervals  of  seven  to  ten  days  until 
January  29,  1902,  the  dose  being. increased  10  c.  c.  with  each  successive  inoculation, 
so  that  at  the  last,  the  eighteenth,  the  total  quantity  given  was  160  c.  c. 

The  total  quantity  of  standard  suspension  of  human  tubercle  bacilli  administered 
to  this  heifer  was  l,797c.  c.  There  was  a  rise  of  temperature  of  from  2°  to  4°  follow- 
ing each  inoculation  after  the  first  one.  The  first  inoculation  caused  no  tempera- 
ture reaction.  The  animal  was  in  strong,  thrifty  condition  at  the  completion  of  the 
series  of  inoculations,  and  continued  to  improve  until  it  was  killed,  August  14, 1902. 
It  was  found  free  from  tuberculosis. 

The  second  animal  treated  was  a  grade  Shorthorn  bull,  which  did  not  react  to 
tuberculin.  Tin's  animal  was  inoculated  as  follows: 

November  19,  1900,  16  c.  c.  intraperitoneally;  March  17,  1901,  13.5  c.  c.  intra- 
venously. Subsequent  inoculations  were  the  same  as  with  the  preceding  animal,  18 
being  given  between  August  23,  1901,  and  January  10,  1902,  the  total  amount  being 
1,710'c.  c. 

This  animal  reacted  very  much  as  the  heifer,  although  somewhat  more  slowly. 
He  remained  in  good  condition  and  apparent  good  health.  On  January  IS,  1902, 
this  bull  was  inoculated  intraperitoneally  with  10  c.  c.  of  a  standard  suspension  of 
bovine  tubercle  bacilli.  This  culture  had  been  tested  and  found  to  be  fatal  for  cat- 
tle in  doses  of  5  c.  c.  intravenously  or  intraperitoneally  within  three  to  eight  weeks. 
The  bull  remained  in  good  condition  until  killed  for  examination  August  13,  1902. 
The  lungs  were  found  to  contain  a  few  nodules  about  one-half  inch  in  diameter, 
surrounded  by  thick  walls  and  containing  caseous  pus  in  which  were  many  tubercle 
bacilli.  These  nodules  did  not  seem  to  be  progressive,  and  appeared  to  be  abscesses 
indicating  the  sites  of  previous  inoculations.  The  lymphatic  glands  about  the 
rectum  were  enlarged  and  caseous.  The  pleura  and  peritoneum  were  covered  with 
a  layer  of  partly  organized  fibrin. 

It  was  thought  that  the  results  of  the  experiments  with  these  two  animals  showed 
that  the  sputum  tubercle  bacilli,  even  in  the  very  large  quantities  in  which  they 
were  employed,  were  incapable  of  causing  general  tubercular  infection,  and  that  the 


60  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

experiment  with  the  latter  (the  bull)  indicated  that  by  treatment  with  such  mate- 
rial the  resistance  to  virulent  Ixivine  bacilli  may  )><•  increased. 

A  further  experiment,  to  test  the  immunizing  value  of  repeated  intravenous  inocu- 
lations of  sputum  cultures  of  tubercle  bacilli  not  virulent  for  cattle,  was  inaugurated 
in  March,  1902.  Four  young  cattle  were  used  in  this  experiment,  which  were 
divided  into  two  groups  as  nearly  equal  as  possible  in  respect  to  age,  si/.e,  and  gen- 
eral condition.  The  animals  of  one  group  were  inoculated  intravenously  seven  times 
between  March  24  and  June  2  with  gradually  increasing  quantities  of  from  10  c.  c. 
to  25  c.  c.  of  standard  suspension  of  tubercle  bacilli.  In  all  125  c.  c.  were  adminis- 
tered, representing  about  0. 16  gram  of  tubercle  bacilli. 

Each  of  the  four  animals — the  two  that  had  been  vaccinated  and  the  two  kept  as 
controls — was  inoculated  July  29  by  injecting  into  the  trachea  10  c.  c.  of  a  standard 
suspension  of  bovine  tubercle  bacilli  known  to  be  virulent  for  cattle. 

One  of  the  vaccinated  cattle  was  killed  October  4  and  a  searching  post-mortem 
examination  revealed  all  of  the  organs  to  be  free  from  all  evidence  of  tubercular 
disease. 

A  control  animal  killed  October  8  showed  the  following  lesions:  Beneath  the  skin 
at  the  point  of  inoculation  there  was  a  globular  abscess  three-quarters  of  an  inch 
in  diameter,  containing  cheesy  pus.  The  lungs  were  studded  upon  the  surface  and 
upon  cross  section  with  grayish  tubercles  one-fourth  to  one-half  inch  in  diameter, 
the  centers  of  which  were  caseous.  The  apex  of  the  right  lung  contained  a  caseous 
area  2  inches  in  diameter.  The  postpharyngeal,  bronchial,  and  mediastinal  lym- 
phatic glands  were  enlarged  and  contained  cheesy  areas. 

The  second  vaccinated  animal  was  killed  October  16,  and  all  of  the  organs  of  the 
body  were  found  free  from  disease  with  the  exception  of  two  globular  swellings  one- 
fourth  to  three-fifths  of  an  inch  in  diameter,  respectively,  at  the  point  of  inoculation. 
One  of  these  was  made  up  of  fibrous  tissue  and  the  other  contained  a  focus  of  caseous 
material  surrounded  by  thick,  fibrous  walls. 

The  second  control  (unvaccinated)  heifer  was  killed  October  16,  and  presented 
the  following  lesions:  Beneath  the  skin  at  the  point  of  inoculation  was  an  abscess  2 
inches  in  diameter  that  contained  cheesy  pus.  All  of  the  inferior  cervical  and  supra- 
sternal  lymph  glands,  as  well  as  the  postpharyngeal,  mediastinal,  bronchial,  and  many 
of  the  mesenteric  lymphatic  glands  were  greatly  enlarged  and  contained  much  case- 
ous material.  The  mucous  membrane  of  the  trachea  was,  on  its  ventral  half,  thickly 
studded  with  oblong,  red,  and  evidently  young  and  progressive  tubercular  growths. 
The  lungs  contained  many  tubercles  evenly  distributed  throughout  their  tissue  and 
averaging  4  to  5  inches  apart,  the  smaller  of  which  were  gray,  while  the  larger  had 
yellow,  cheesy  centers. 

VON  BEHRING'S  INVESTIGATIONS. 

A  long  series  of  investigations  relative  to  the  production  of  immu- 
nity  in  cattle  has  been  made  by  Von  Behring,51  whose  first  paper  on 
the  subject  was  published  in  December,  1901.  His  method  has  been 
modified  from  time  to  time,  but  he  has  no  doubt  succeeded  in  produc- 
ing a  high  degree  of  immunity  in  some  of  his  experimental  animals. 
His  work  has  been  of  much  value  in  showing  the  effect  of  different 
doses  of  human  tubercle  bacilli  when  inoculated  upon  cattle,  as  well 
as  in  directing  attention  to  immunization  as  a  practical  means  of  com- 
bating tuberculosis  in  cattle.  As  the  result  of  experiments  with 
several  hundred  young  cattle,  he  states  that  one  of  his  weaker  cultures 
in  doses  of  one-tenth  of  a  milligram  injected  intravenously  does  not 
produce  the  slightest  effect  upon  the  animal  either  as  to  its  appearance 
or  temperature.  Infection  with  1  milligram  of  this  culture  causes  a 
slight  rise  of  temperature,  not  exceeding  1°  C.,  which  as  a  rule  is  fol- 
lowed by  a  return  to  the  normal  temperature  after  two  or  three  days. 
Doses  of  1  centigram  and  larger  amounts  cause  very  threatening 
symptoms,  but  with  the  largest  doses  used  the  disease  developed  was 
not  so  great  but  that  the  animals  made  a  complete  recovv  ry.  The 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  61 

post-mortem  examination  of  an  animal  which  had  received  an  intra- 
venous injection  of  2  centigrams  of  this  culture  showed  that  no  points 
of  disease  remained  in  the  body. 

The  method  first  recommended  for  protecting  animals  in  practical 
operations  was  to  take  cattle  from  5  to  7  months  of  age  that  did  not 
react  to  the  tuberculin  test  and  to  give  by  intravenous  injection,  as  the 
first  dose,  i  milligram  of  a  serum  culture  4  to  6  weeks  old.  Four 
weeks  later  the  animal  was  given  in  like  manner  a  dose  of  25  milli- 
grams of  the  same  culture.  In  his  later  papers  Von  Behring  recom- 
mends the  use  of  this  same  culture  after  it  has  been  dried  in  a  vacuum 
at  a  low  temperature.  In  order  to  immunize  cattle  this  is  suspended 
in  1  per  cent  salt  solution  and  given  by  intravenous  injection.  The 
first  dose  is  4  milligrams,  and  the  second  dose,  which  is  to  be  given  at 
the  earliest  twelve  weeks  after  the  first  dose,  is  2  centigrams. 

The  inoculation  material,  or  "  vaccine,"  is  furnished  in  the  dry 
powdered  form,  and  is  supposed  to  remain  active  for  at  least  four 
weeks.  The  powder  is  of  course  made  up  of  an  enormous  number  of 
human  tubercle  bacilli,  which  are  so  minute  and  light  that  they  are  liable 
to  be  taken  up  by  slight  currents  of  air,  and  unless  suitable  precautions 
are  taken  they  may  be  breathed  by  the  persons  present  at  the  time  the}r 
are  examined  or  when  they  are  being  prepared  for  use  in  immunizing 
cattle.  This  form  of  vaccine  is  therefore  considered  objectionable  and 
unsafe  by  some  authorities,  and  the  preference  is  given  to  immunizing 
material  which  is  prepared  in  the  laboratory  in  liquid  form. 

The  cattle  immunized  by  the  Von  Behring  method  appear  to  acquire 
a  considerable  degree  of  immunity,  but  some  of  them  certainly  have 
not  had  sufficient  to  enable  them  to  resist  fatal  doses  of  the  bovine 
tubercle  bacillus.  It  is  believed  by  Von  Behring  that  immunization 
by  this  method  will  protect  cattle  against  natural  infection  when  they 
are  exposed  in  stables  to  diseased  cattle;  but,  unfortunately,  some  of 
the  cattle  reported  upon  as  tested  were  not  immunized  by  the  latest 
process  which  he  recommends,  and  consequently  do  not  furnish  an 
indication  as  to  its  value.  Further  experiments  will  be  required  to 
establish  the  efficacy  of  Von  Behring\s  method,  and  particularly  to 
determine  the  length  of  time  that  the  dried  tubercle  bacilli  will  retain 
their  activity  under  the  different  conditions  to  which  they  are  likely  to 
be  exposed. 

To  protect  the  operator  from  the  danger  of  manipulating  bacilli  used 
for  the  preparation  of  the  vaccinal  emulsion,  and  to  render  this  as 
homogeneous  as  possible,  Vallee  and  Panisset 52  recommend  the  follow- 
ing plan  of  procedure: 

Grind  the  dried  bacilli  with  2  or  3  drops  of  glycerin  in  a  short-necked  Wurtz 
matrass,  using  glass  balls,  then  emulsionize  progressively  in  the  desired  quantity  (2  c.  c. 
for  4  milligrams  of  bacilli)  of  physiological  serum  having  8  per  1,000  of  chloride  of 
sodium  to  which  is  added  1 J  grams  per  1,000  of  carbonate  of  sodium.  The  addition 
of  this  salt  favors  the  homogeneousness  of  the  emulsion  and  has  no  injurious  effect 
upon  the  animals  or  upon  the  vaccine. 


62  TUBERCULOSIS    OP   THE    FOOD-PRODUCING    ANIMALS. 

In  November,  1902,  Doctor  Von  Bohr  ing-  sent  2  bovine  animals  pro- 
tected by  his  method  from  Marburg  to  the  university  at  Leipzig  for 
the  purpose  of  being  tested  as  to  their  degree  of  resistance  against 
artificial  infection  with  bovine  tuberculous  material.  The  tests  were 
carried  on  during  the  autumn  of  1904. 

No.  1  had  received  intravenous  injections  of  bovine  tubercle  bacilli,  the  activity  of 
which  had  been  diminished  by  treatment  with  trichloride  of  iodine,  followed  by 
intravenous  injections  of  bovine  tubercle  bacilli  dried  in  vacuo,  and  an  injection  into 
the  anterior  chamber  of  the  eye  of  virulent  human  tubercle  bacilli.  The  eye  became 
tabercoiooa  and  was  removed  by  operation.  Finally  the  animal  was  subjected  to  a 
series  of  six  injections  with  increasing  quantities  of  fresh  human  tubercle  bacilli. 

No.  2  had  previously  been  injected  with  dead  human  tubercle  bacilli,  cultivated  in 
the  rat  and  with  fresh  human  tubercle  bacilli.  Following  this  it  had  received  an 
intravenous  injection  of  fresh  bovine  tubercle  bacilli,  and  finally  it  had  been  twice 
inoculated  intravenously  with  avian  tubercle  bacilli  dried  in  vacuo. 

Both  animals  were  gradually  infected,  subcutaneously  and  intravenously,  with 
bovine  tubercle  material,  6  other  tubercle-free  young  cattle  being  employed  as  con- 
trols. T\vo  other  young  cattle  were  utilized  for  the  purpose  of  controlling  the  method 
of  feeding  and  the  general  hygienic  conditions. 

The  general  conclusion  arrived  at  was  that  the  animals  treated  by  the  Marburg 
method  showed  a  greater  degree  of  resistance  against  artificial,  subcutaneous,  and 
intravenous  infection  with  bovine  tubercle  virus  than  those  not  treated.  The  grounds 
for  this  conclusion  were: 

1.  The  absence  of  any  local  change  at  the  point  of  inoculation  when  infectecUwith 
slightly  virulent  material,  which  in  control  No.  6  produced  tuberculous  infiltration 
at  the  point  of  inoculation  and  tuberculous  enlargement  and  caseation  of  the  neigh- 
boring lymph  glands. 

2.  The  very  trifling  changes  at  the  point  uf  inoculation  and  the  absence  of  any 
tuberculous  change  whatever  in  the  local  lymph  glands  in  No.  1  when  subcutane- 
ously inoculated  with  very  virulent  material,  which  caused  in  control  No.  13  exten- 
sive infiltration  and  ulceration  at  the  point  of  inoculation,  extensive  swelling  and 
caseation  of  the  neighboring  lymph  glands,  and  embolic  tuberculosis  of  the  lungs, 
liver,  and  spleen. 

3.  The  absence  of  any  kind  of  tuberculous  change  in  neighboring  lymph  glands 
even  in  cases  where  subcutaneous  injection  of  very  virulent  material  led  to  the 
formation  of  a  caseous  tuberculous  abscess  at  the  point  of  inoculation  and  isolated 
embolic  tubercles  in  the  kidneys  (No.  2). 

In  control  No.  14  the  subcutaneous  injection  of  similar  material  produced  exten- 
sive tuberculous  infiltration  at  the  point  of  inoculation,  extensive  tuberculous  swel- 
ling and  caseation  of  neighboring  lymph  glands,  and  embolic  tuberculosis  of  the 
lungs  and  spleen. 

4.  When  virulent  tubercle  bacilli  were  injected  into  the  veins  the  increased  resist- 
ance was  principally  shown  by  the  trifling  degree  of  general  disturbance  produced 
and  by  the  speedy  and  substantial  improvement  in  the  condition  of  the  protected 
animal,  which  continued  to  live  for  five  months  and  three  weeks  longer.     The  animal 
was  eventually  slaughtered  on  account  of  acute  brain  disease,  probably  of  tubercu- 
lous origin.     Controls  Nos.  21  and  22,  injected  with  a  similar  amount  of  virulent 
material,  died  in  twenty-eight  and  thirty-eight  days,  respectively. 

The  protected  animals  were  by  no  means  absolutely  proof  against  the  disease. 
When  the  quantity  administered  was  sufficient  both  animals  suffered  from  tulierculous 
infection. 

The  tuberculin  test  is  unreliable  in  cattle  previously  treated  with  attenuated  bovine 
or  human  tubercle  bacilli  unless  a  long  period  (not  less  than  six  months)  has 
elapsed  since  the  last  infectious  material  was  injected.  The  protected  animals  did 
not  react  to  tuberculin  even  when  they  were  suffering  from  tuberculous  changes  both 
at  the  point  of  inoculation  and  in  their  internal  organs.  As  neither  of  the  protected 
animals  was  immunized  by  the  double  inoculation  method  with  weakened  human 
tubercle  bacilli  according  to  Von  Behring's  present  method,  the  foregoing  conclusions 
must  not  l>e  applied  to  this  method. 

Eber53  considers  the  results  so  far  obtained  from  this  and  other 
experiments  as  very  encouraging. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  63 

EXPERIMENTS   BY   HUTYRA. 

Some  important  experiments  were  made  by  Hutyra,54  under  com- 
mission of  the  Hungarian  department  of  agriculture,  in  order  to 
determine  to  what  extent  vaccination  according  to  Von  Beh  ring's 
method  increases  the  immunity  of  cattle  against  artificial  infection 
with  virulent  bovine  tubercle  bacilli. 

Two  calves  9  months  old  were  treated  with  Von  Behring's  vaccine.  The  first  dose 
was  0.004  gram,  and  forty  days  later  a  second  dose  of  0.01  gram  was  administered. 
Two  months  after  the  second  vaccination  both  of  these  animals,  together  with  2 
control  animals  of  the  same  breed,  received  an  intravenous  inoculation  of  0.0-  gram 
of  virulent  bovine  bacilli.  Two  weeks  after  this  infection  the  control  animals  were 
very  sick,  and  one  was  killed  at  the  end  of  four  weeks  and  the  other  at  the  end  of 
six  weeks  from  the  inoculation,  both  being  in  a  dying  condition.  The  examination 
showed  with  both  animals  an  extensive  miliary  tuberculosis  of  the  lungs  and  pectoral 
lymph  glands.  The  vaccinated  animals  quickly  recovered  from  the  reaction  follow- 
ing the  infection,  but  had  some  fever  afterwards,  though  their  weight  increased  and 
they  presented  no  other  symptoms  of  disease.  They  were  killed  two  and  one-half 
months  after  infection,  and  examination  showed  in  both  cases  slight  tuberculosis  in 
isolated  parts  of  the  lungs  and  in  the  pectoral  lymphatic  glands. 

An  animal  of  the  same  breed  and  age  as  those  in  the  experiment  just  reported  was 
likewise  twice  vaccinated.  Two  months  after  the  second  vaccination  this  animal 
and  a  control  animal  were  given  a  subcutaneous  injection  of  0.02  gram  of  a  culture 
of  virulent  bovine  bacilli.  The  effect  with  the  two  animals  was  much  the  same,  only 
there  developed  at  the  point  of  inoculation  in  the  control  animal  a  much  larger 
swelling  than  with  the  vaccinated  animal.  The  animals  were  killed  two  and  one- 
half  months  later,  and  there  was  found  in  the  vaccinated  animal  only  a  caseous  spot 
the  size  of  a  bean  at  the  point  of  inoculation,  with  enlargement  of  the  corresponding 
prescapular  lymph  glands,  while  with  the  control  animal  there  was  not  only  an 
extensive  lesion  at  the  point  of  inoculation,  but  there  were  tubercles  in  the  lungs, 
spleen,  and  kidneys,  and  the  beginning  of  pearl  disease  on  the  pleura. 

In  another  experiment  4  young  cattle  from  9  to  12  months  old  were  twice  vaccin- 
ated with  Von  Behring's  material  with  an  interval  of  forty  days.  After  two  months 
had  elapsed  these  animals  with  two  controls  were  fed  with  cultures  of  virulent  bovine 
bacilli,  which  had  no  apparent  effect  upon  their  health.  Five  months  after  the  second 
vaccination,  and  two  months  after  the  animals  were  fed  with  bovine  culture,  all  6 
calves  were  given  an  intravenous  injection  of  0.025  gram  of  a  culture  of  bovine  bacilli. 
All  of  these  animals  gave  a  strong  temperature  reaction.  While,  however,  with  2  of 
the  inoculated  calves  the  abnormal  symptoms  soon  disappeared,  with  a  third  the 
fever  continued  and  there  was  little  gain  in  weight,  and  with  a  fourth  the  result  was 
so  serious  that  it  was  necessary  to  kill  the  animal  five  weeks  later,  it  being  then  very 
sick,  and  the  post-mortem  examination  showed  extensive  tuberculosis  of  the  lungs  and 
lymnh  glands.  Both  control  animals  became  very  sick  after  the  infection,  and  on 
post-mortem  examination  were  found  to  have  extensive  tuberculosis  of  the  lungs  and 
lymph  glands,  and  one  of  them  had  besides  tubercles  and  tubercular  ulcers  of  the 
intestinal  mucous  membrane.  The  3  vaccinated  animals  which  remained  living  were 
killed  three  months  after  the  intravenous  infection  and  showed  moderate  tubercular 
lesions  in  the  lymph  glands  of  different  parts  of  the  body.  With  one  there  was  a 
focus  of  catarrhal  pneumonia  in  the  lungs  and  with  another  there  were  soft  growths 
up  to  the  size  of  a  bean  upon  the  pleural  and  peritoneal  surfaces  of  the  diaphragm. 
Decided  lesions  from  alimentary  infection  were  only  present  in  one  case  and  with 
this  the  infection  had  occurred  through  the  mucous  membrane  of  the  throat. 

A  final  experiment  was  made  with  different  stocks  of  tul>ercle  bacilli;  one  of  these 
was  from  a  monkey  and  two  from  human  sources.  The  cultures -of  the  three  stocks 
presented  the  peculiarities  of  human  tubercle  bacilli.  For  vaccination,  cultures  4 
weeks  old  which  had  been  grown  on  glycerin  potato  were  used  without  lx?ing  dried, 
each  animal  receiving  the  first  time  0.005  gram  and  five  and  a  half  weeks  later  0.025 
gram  injected  into  the  jugular  vein.  The  animals  were  3A  to  9  months  old.  There 
was  no  increase  of  temperature  following  the  first  injection,  but  after  the  second 
injection  2  animals  had  a  fever  lasting  two  days.  Seven  weeks  after  the  second, 
vaccination  all  3  animals,  with  a  control,  received  0.02  gram  of  a  glycerin-potato 
culture  of  virulent  bovine  bacilli  by  injection  into  the  jugular  vein.  The  vaccinated 
cattle  had,  as  a  result  of  this  inoculation,  a  marked  increase  in  temperature,  which 
subsided  and  left  the  animals  in  a  normal  condition.  Three  months  after  the  inocu- 
lation with  bovine  bacilli  the  3  animals  were  killed,  and  showed  on  examination 


6-1  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMAL-. 

insignificant  tuberculous  lesions  in  the  internal  organs.  In  one  case  the  lungs  were 
entirely  healthy  and  only  a  fresh  connective  tissue  growth  on  the  costal  pleura  led 
to  the  suspicion  that  it  was  caused  by  the  inoculation.  In  a  second  cane  the  peri- 
bronchial  lymph  glands  alone  contained  very  small  calcified  tubercles.  In  this 
experiment  the  tubercle  bacilli  from  the  monkey  and  from  the  two  human  sources 
produced  even  more  favorable  results  than  were  obtained  in  the  first  experiment 
with  Von  Behring's  original  vaccine. 

A  peculiar  behavior  toward  tuberculin  was  observed  with  these  cattle  which  had 
been  twice  vaccinated  and  afterwards  infected  with  virulent  bovine  bacilli.  Of  G 
cases  which  were  tested  with  tuberculin  two  and  one-half  months  after  the  virulent 
infection,  5  cattle  did  not  react  at  all,  and  with  1  only  \yas  there  a  rise  of  temperature 
from  39°  to  40.8°  C.  Tubercular  lesions  were  found  in  5  of  these  animals  at  the 
post-mortem  examination.  This  striking  insensibility  of  the  first  5  cattle  to  tuber- 
culin recalls  the  similar  behavior  of  cattle  which  as  a  result  of  natural  infection  are 
already  very  sick,  as  well  as  of  those  which  had  a  short  time  previously  received  a 
larger  dose  of  tuberculin,  in  which  cases  it  often  happens  that  no  reaction  occurs. 
It  appears,  therefore,  that  as  a  consequence  of  a  heavy  infection  or  a  saturation  of 
the  organism  with  the  toxic  products  of  the  tuberculosis  bacilli  the  sensibility  toward 
tuberculin,  or  at  least  toward  small  doses  of  tuberculin,  becomes  for  a  certain  time 
lessened. 

Hutyra 55  stated  in  his  report  to  the  International  Veterinary  Con- 
gress at  Budapest  in  1905  that  his  conclusions  in  regard  to  the  immu- 
nization of  bovine  animals  against  tuberculosis  were  at  follows: 

An  intravenous  injection,  once  repeated,  of  human  tubercular  bacilli,  after  Von 
Behring's  method  or  some  similar  one,  increases  to  a  very  considerable  extent  the 
power  of  resistance  in  cattle  to  artificial  pearl-disease  infection. 

The  process  is  innocuous  to  sound  cattle,  and  presents  no  difficulties  in  its  carrying 
into  practice. 

The  question  whether,  and  if  so,  how  far,  the  immunity  produced  in  this  wax- 
extends  to  natural  infection,  finds  no  solution  in  the  results  of  past  experience;  to 
solve  this  problem  accurate  observations  of  inoculated  animals,  continued  for  years, 
will  still  be  necessary. 

A  similar  inoculative  protection  against  artificial  infection  is  apparently  afforded 
by  a  single  subcutaneous  injection  with  cultures  of  human  tubercular  bacilli. 

THOMASSEN'S  EXPERIMENTS. 

Experiments  made  by  Thoniassen56  in  1902  indicate  that  consider- 
able immunity  may  be  produced  by  inoculating  cattle  with  human 
bacilli. 

A  young  bull  received  by  intravenous  injection  January  9,  1902,  30  milligrams  of 
human  bacilli  which  had  been  cultivated  on  potato  since  July,  1900.  The  bacilli 
were  given  fresh.  If  dried  they  would  have  been  reduced  to  about  6  or  7  milli- 
grams, and  besides,  desiccation  reduces  the  virulence  of  tubercle  bacilli.  Until 
January  22  the  animal  presented  no  symptoms,  but  on  that  date  the  temperature 
commenced  to  rise,  and  on  the  2.'!d  reached  40.9°  C.  The  temperature  continued  to 
fluctuate  between  40°  and  41°  C.  until  the  first  days  of  February.  The  animal  con- 
tinued to  drink  milk  but  did  not  gain  in  weight  and  its  appearance  was  not  satisfac- 
tory. From  the  7th  of  February  the  temperature  became  normal,  and  toward  the 
beginning  of  March  the  calf  gained  in  weight  and  appeared  to  be  in  perfectly  normal 
condition.  April  29  the  animal  was  tested  with  tuberculin  but  did  not  react.  The 
immunity  was  tested  by  intravenous  injection  June  12  of  40  milligrams  of  culture  of 
bovine  bacilli.  The  day  of  the  injection  a  marked  rise  of  temperature  was  noticed, 
which  persisted  for  five  days,  but  the  appetite  remained  normal,  the  respiration  did 
not  increase  in  frequency,  and  there  was  no  cough.  The  animal  reacted  when  tested 
with  tuberculin  August  17,  and  was  killed  for  examination  September  25.  The 
autopsy  revealed  about  ten  tubercles  in  each  lung,  some  of  which  were  as  large  as  a 
pea,  but  the  majority  were  the  size  of  a  millet  seed.  Guinea  pigs  inoculated  from 
these  tubercles  died  of  generalized  tuberculosis.  A  single  bronchial  gland  contained 
some  tubercles,  but  guinea  pigs  inoculated  from  this  gland  did  not  contract  the  dis- 
ease. The  clinical  symptoms  would  indicate  that  the  few  lesions  observed  exclu- 
sively in  the  lungs,  and  that  might  be  considered  as  in  process  of  healing,  had  been 
produced  by  the  infection  with  the  human  bacilli;  but  the  tuberculin  test,  on  the 
contrary,  would  lead  to  the  conclusion  that  the  slight  infection  which  was  found 
dated  from  the  injection  of  the  bovine  bacilli.  Even  if  the  latter  supposition  were 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  65 

correct,  the  animal  appeared  to  possess  a  degree  of  immunity  which  is  seldom  seen 
in  animals  which  have  not  been  immunized. 

As  a  control  animal  to  determine  the  virulence  of  the  bovine  bacilli,  calf  No.  2 
was  used.  This  animal  was  given  30  milligrams  of  the  fresh  culture  by  intravenous 
injection  on  June  28.  This  inoculation  caused  at  first  but  a  slight  increase  in  tem- 
perature, which  increased  July  9  to  41°  C.  and  remained  above  that  point  for  about 
a  week.  The  animal  remained  constantly  in  a  recumbent  position  and  died  July  17. 
On  examination  the  lungs  were  found  studded  with  recent  miliary  tubercles. 

Calf  No.  3  received  March  4, 1902,  by  intravenous  injection,  25  milligrams  of  human 
tubercle  bacilli,  which  had  been  passed  once  through  a  guinea  pig  and  cultivated  for 
three  months  on  potato.  The  only  symptom  caused  by  this  inoculation  was  a  slight 
rise  in  temperature.  Without  testing  with  tuberculin,  this  calf  was  infected  June  11 
with  40  milligrams  of  fresh  bovine  bacilli,  such  as  were  used  in  the  inoculation  of 
No.  2.  The  animal  neither  coughed  nor  lost  appetite  and  its  condition  remained 
good.  It  was  tested  August  17  and  reacted,  and  was  again  tested  with  a  like  result 
October  16.  It  received  a  third  infection  November  3  by  intravenous  injection  of  45 
milligrams  of  bovine  bacilli,  which  produced  no  symptom  other  than  a  slight  rise  of 
temperature  lasting  about  a  week.  This  calf  was  killed  December  18,  and  the  exami- 
nation revealed  a  considerable  number  of  tubercles  in  the  posterior  part  of  the  two 
lungs.  These  tubercles  were  all  calcined  to  such  a  degree  that  it  was  impossible  to 
make  a  section  of  them  with  a  bistoury.  After  crushing  and  examining  these  tuber- 
cles no  bacilli  could  be  discovered.  Three  tubercles  were  found  in  a  bronchial  gland 
which  were  less  advanced  in  retrogression,  but  it  was  not  yet  determined  whether 
they  contained  tubercle  bacilli. 

Calf  No.  4  was  inoculated  February  6, 1902,  in  the  anterior  chamber  of  the  eye  with 
a  few  drops  of  an  emulsion  of  human  bacilli.  From  February  15  to  March  7  there 
was  an  increase  of  temperature  varying  from  0.5°  to  1.7°  C.  Tested  with  tuberculin 
April  29  and  August  17,  it  reacted  on  both  occasions.  September  3  this  calf  -was 
given  by  intravenous  injection  30  milligrams  of  a  culture  of  bovine  bacilli.  During 
the  twenty-four  hours  following  this  injection  the  temperature  rose  to  40.2°  C.,  but 
no  other  symptom  was  noticed  for  several  days.  Beginning  with  September  12,  the 
animal  coughed  and  had  frequent  respiration,  but  these  symptoms  disappeared  after 
a  few  days.  October  11  it  was  tested  with  tuberculin  and  reacted.  This  calf  was 
killed  October  24,  and  the  most  careful  examination  did  not  reveal  the  least  lesion 
in  either  the  abdominal  or  thoracic  organs.  Two  guinea  pigs  were  inoculated  with  an 
emulsion  made  from  a  suspicious  gland,  but  no  effect  was  produced.  The  posterior 
chamber  of  the  eye~ contained  a  caseous  mass  in  which  were  some  calcified  points, 
and  in  this  tubercular  material  the  bacilli  could  still  be  found.  A  retropharyngeal 
gland  was  also  affected. 

Calf  No.  5,  12  days  old,  was  given  8  milligrams  of  a  fresh  culture  of  bovine  bacilli 
September  8.  During  the  first  week  the  temperature  rose  a  little  above  the  normal, 
but  it  was  only  from  the  fifteenth  day  that  there  was  a  considerable  rise.  The  tem- 
perature became  normal  October  30,  but  during  this  month  there  had  been  little  or  no 
gain  in  weight.  November  3  it  received  an  intravenous  injection  of  30  milligrams  of 
the  same  culture,  which  immediately  caused  a  marked  rise  in  temperature.  It 
coughed,  drank  only  half  of  its  milk,  and  had  rapid  respiration.  From  the  eighth  day 
after  the  inoculation  its  general  condition  considerably  improved,  and  by  the  eleventh 
day  it  was  very  nearly  in  the  condition  in  which  it  was  before  the  second  infection. 
Desiring  to  learn  the  character  of  the  lesions  produced  by  the  injection  of  the  8  mil- 
ligrams of  bovine  culture  the  investigator  killed  the  animal  on  November  12,  and 
the  examination  showed  a  number  of  miliary  tubercles  in  the  lungs  containing  bacilli 
capable  of  infecting  guinea  pigs.  The  bronchial  glands  were  also  affected. 

From  these  experiments  it  was  concluded  that  bovine  animals  bear  very  well  a 
dose  of  30  milligrams  of  a  culture  of  human  bacilli  injected  directly  into  the  veins. 
Also  that  a  first  infection  does  not  cause  a  rise  of  temperature  until  ten  or  fifteen 
days  after  the  inoculation,  while  with  the  second  or  third  infection  with  bacilli  the 
increase  of  temperature  appears  within  twenty-four  hours. 

After  experimenting  with  different  methods  of  immunization  for 
more  than  three  years,  Thomassen 5T  reaches  the  following  conclusions: 

1.  It  is  now  established  that  it  is  possible  to  obtain  a  certain  degree  of  active 
immunity  in  regard  to  tuberculosis. 

2.  The  immunization  of  young  cattle  is  a  powerful  addition  to  the  means  of  hasten- 
ing the  extinction  of  tuberculosis. 

3.  It  should  be  undertaken,  after  testing  with  tuberculin,  as  early  as  possible — i.  e., 
at  the  age  of  6  weeks,  when  the  animal  has  not  yet  been  exposed  to  the  danger  of 
contamination. 

1881— No.  38—06 5 


66  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

4.  The  use  for  this  purpose  of  human  bacilli,  of  a  low  degree  of  virulence,  and  in  a 
fresh  condition,  is  preferable  to  that  of  other  vaccines  which  are  mentioned. 

5.  For  the  first  injection  1  milligram  of  bacilli  is  used,  which  may  be  preceded  by 
a  few  injections  of  bovine  tuberculin  (this  is  highly  recommended,  particularly  for 
animals  only  a  few  weeks  old).      The  dose  is  increased  each  time,  at  a  month's- 
interval,  to  10  and  then  to  20  milligrams.     The  intravenous  injection  of  bacilli  should 
never  cause  the  formation  of  an  abscess  at  the  point  of  injection. 

6.  Care  should  especially  be  taken  to  crush  perfectly  the  bacilli,  so  as  to  prevent 
pulmonary  lesions  or  embolic  origin. 

7.  The  application  of  the  vaccination  on  a  large  scale  will  be  attended,  in  practice, 
with  difficulties;  among  others  the  danger  resulting  to  man  from  the  manipulation 
of  virulent  products. 

8.  It  is  very  important  to  determine  accurately  the  duration  of  the  immunity 
following  the  vaccination. 

9.  It  may  be  admitted  that  the  animal  will  be  better  able  to  resist  the  influence  of 
a  natural  infection  than  that  of  a  large  quantity  of  bovine  bacilli  of  great  virulence 
placed  directly  in  the  circulation. 

KLIMMER'S  INVESTIGATIONS. 

Very  important  experiments  in  immunization  have  recently  been 
reported  by  Klimmer,58  of  Dresden.  This  investigator  made  a  number 
of  experiments  with  reference  to  the  modification  of  the  virulence  of 
the  .tubercle  bacillus  by  passing  it  through  different  cold-blooded 
animals.  By  long-continued  experiments  with  carp  it  was  observed 
that  by  living  in  cold-blooded  organisms  the  tubercle  bacillus  gradu- 
ally lost  its  virulence,  and  when  guinea  pigs  were  inoculated  with  it 
the  period  of  incubation  and  the  duration  of  the  disease  were  increased. 
By  the  use  of  a  species  of  salamander  in  such  experiments  the  tubercle 
bacillus  finally  lost  entirely  its  virulence  for  mammals.  The  culture 
of  this  fully  acid-fast  avirulent  tubercle  bacillus  had  the  same  appear- 
ance as  that  of  the  human  tubercle  bacillus.  Rabbits  and  guinea  pigs 
inoculated  with  large  quantities  of  this  bacillus  remained  in  a  healthy 
condition.  Even  the  intravenous  injection  of  1  centigram  of  the 
culture  failed  to  produce  any  tubercular  changes  in  the  organs. 

After  the  harmlessness  for  mammals  of  the  avirulent  tubercle  bacillus  became  known, 
experiments  were  made  with  it  for  the  immunization  of  animals  against  tuberculosis. 
For  this  purpose  rabbits  and  cattle  were  used.  The  vaccinations  were  made  partly 
by  intravenous  and  partly  by  subcutaneous  injection,  and  the  testing  of  the  immunity 
was  conducted  by  natural  as  well  as  by  artificial  infection  experiments.  The  rabbits 
immunized  with  the  avirulent  tubercle  bacillus  were  in  the  first  place  tested  by  arti- 
ficial infection  with  a  stock  of  human  tubercle  bacilli  which  was  pathogenic  for 
rabbits,  and  it  was  demonstrated  in  this  way  that  these  animals  had  acquired  abso- 
lute immunity  against  human  tubercle  bacilli.  Afterwards  the  immunized  rabbits 
were  tested  by  infection  with  a  very  virulent  bovine  bacillus  and  proved  to  have 
acquired  a  very  high  or  even  absolute  immunity  against  this  active  germ. 

Cattle  were  given  intravenous  injections  of  the  avirulent  tubercle  bacillus  without 
causing  any  injury  to  their  health,  and  tolerably  large  quantities  wore  injected  sub- 
cutaneously  without  producing  either  local  or  general  disturbance.  The  immuniza- 
tion was  carried  out  with  several  animals  by  intravenous  injection  and  with  others 
by  subcutaneous  injection,  and  the  immunized  calves  were  afterwards  tested  partly 
by  natural  and  partly  by  artificial  infection.  These  animals  showed  a  complete 
resistance  to  natural  infection  up  to  the  time  of  reporting,  and  during  the  period  of 
a  year  which  had  elapsed,  although  the  animals  were  repeatedly  tested  with  tuber- 
culin, none  had  reacted,  while  the  control  animals  had  shown  33  to  36  per  cent  of 
positive  reactions.  The  experiments  with  artificial  infection  were  not  completed  at 
the  time  of  reporting. 

Klimmer  also  used  for  immunizing  cattle  an  attenuated  human  bacillus,  which 
was  harmless  both  for  the  persons  using  it  and  for  the  animals.  It  was  obtained  by 
making  pure  cultures  directly  from  the  original  source  and  without  passage  through 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  67 

any  animal.  In  order  that  the  use  of  this  material  for  vaccination  might  be  harm- 
less for  the  veterinarian  it  was  not  furnished  in  the  dry  condition  from  which  it  is 
easily  transformed  into  dust,  thereby  becoming  dangerous,  but  was  taken  directly 
from  the  culture  and  made  into  a  suspension  in  the  laboratory  where  it  was  culti- 
vated, so  that  it  could  be  used  in  practice  for  immunizing  without  further  manipula- 
tion. This  suspension  of  bacilli  remains  unchanged  and  retains  its  immunizing  value 
for  four  weeks.  In  order  to  reduce  to  a  minimum  the  danger  of  infection  through 
accidents  and  awkwardness,  the  tubercle  bacilli  are  artificially  attenuated  in  their 
virulence  by  heating  at  52°  to  53°  C.  Such  an  attenuation  of  the  vaccination  mate- 
rial does  not  affect  its  immunizing  value. 

The  use  of  this  suspension  of  attenuated  tubercle  bacilli  by  intravenous  injection 
into  cattle  is  harmless,  and  even  subcutaneous  injections  produced  no  local  swellings 
with  calves,  whereas  suspensions  of  the  unattenuated  bacilli  caused  swellings  from 
the  size  of  a  nut  to  that  of  a  goose  egg,  with  the  formation  of  abscesses.  From  the 
experience  so  far  obtained  it  appears  that  cattle  may  be  immunized  by  subcutaneous 
injection  of  this  attenuated  vaccine  material.  This  simplifies  the  operation,  as  the 
intravenous  injection  requires  more  time  and  is  more  difficult. 

Klimmer  is  of  the  opinion  that  the  tubercle  bacilli  used  for  this  purpose  should 
not  have  been  cultivated  too  long  on  artificial  media,  and  that  they  should  have 
acquired  as  little  as  possible  of  the  saprophytic  habit  of  growth. 

Such  vaccine  material  made  in  the  Dresden  Hygienic  Institute  has  been  practi- 
cally tested  since  1903  on  a  royal  estate  near  Dresden,  where  the  avirulent  bacillus 
has  also  been  used.  Over  80  per  cent  of  the  cows  and  over  40  per  cent  of  the  young 
cattle  at  this  place  reacted  to  tuberculin.  The  immunized  calves  were,  therefore, 
exposed  to  a  heavy  infection,  especially  as  they  were  stabled  among  the  tuberculous 
animals.  In  the  two  years  during  which  the  investigations  have  been  in  progress  it 
has  been  established  that  the  immunization  of  calves  with  this  vaccine  is  free  from 
danger.  No  losses  have  occurred  from  vaccination.  Of  about  60  calves  treated, 
some  have  been  slaughtered  and  others  have  died  from  various  causes,  but  in  none 
of  these  could  signs  of  tuberculosis  be  discovered.  Neither  have  any  of  the  immu- 
nized animals  reacted  to  tuberculin.  The  immunized  calves  developed  in  a  superior 
manner,  proving  that  the  immunization  had  no  detrimental  effect  upon  them. 

The  immunized  calves  and  the  control  calves,  which  have  been  standing  mixed 
together  almost  since  their  birth,  have  been  tested  with  tuberculin.  Of  the  control 
calves,  which  of  course  were  not  immunized,  14  were  tested  at  one  time  and  6 
reacted,  and  at  another  time  10  were  tested  and  3  reacted.  Of  the  calves  immu- 
nized with  the  Dresden  vaccination  material  not  a  single  one  has  reacted,  neither 
when  tested  a  month  after  immunization  nor  when  the  test  was  made  one  and  one- 
half  years  afterwards. 

WORK   OF   KOCH   AND   OTHERS. 

In  a  recent  and  very  important  paper  Koch,  Schiitz,  Neufeld,  and 
Mieszner59  state  that  in  their  experimental  investigations  they  grad- 
ually reached  a  simple  and  safe  method  by  which  animals  could  be 
given  a  high  degree  of  iramunit}r  by  one  or  two  injections  of  living 
cultures  of  tubercle  bacilli.  With  cattle  they  obtained  a  complete 
immunization  with  only  two  injections,  using  at  first  an  attenuated 
culture  of  the  bovine  bacillus.  The  following  striking  experiment 
illustrates  this  fact: 

Calf  XIII,  weight  345.4  pounds,  received  an  intravenous  injection  of  1  centigram 
of  an  attenuated  bovine  culture  on  August  25,  1902.  A  second  injection  of  a  like 
amount  of  the  same  culture  was  adminis'ered  in  the  same  manner  October  17,  1902. 
The  degree  of  immunity  which  this  calf  had  acquired  by  these  treatments  was  tested 
by  injecting  intravenously  1  centigram  of  a  virulent  bovine  culture  December  24, 
1902,  a  control  calf  being  inoculated  at  the  same  time  and  in  the  same  manner  with 
a  like  amount  of  the  virulent  culture.  As  a  result  of  the  inoculation  with  the  viru- 
lent culture,  the  unprotected  control  calf  died  January  16,  1903,  with  miliary  tuber- 
culosis of  the  lungs.  The  protected  calf  resisted  the  inoculation,  and  when  killed, 
on  August  11,  1903,  was  found  healthy. 

A  degree  of  immunity  which  is  sufficient  to  protect  completely  an 
animal  from  such  a  virulent  bovine  germ  as  was  used  to  test  this  calf, 
and  which  may  be  conferred  by  two  vaccinations,  is  worthy  of  very 


68 


TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 


serious  attention.  A  table  has  therefore  been  prepared  by  condensing 
a  more  complete  one  given  by  the  authors  which  presents  the  impor- 
tant facts  relative  to  a  series  of  experiments  since  made  by  them. 

All  of  the  calves  used  in  these  experiments  were  first  tested  with  tuberculin  and 
none  were  taken  which  showed  a  rise  of  temperature  of  more  than  0.5°  C.  The 
second  vaccination  generally  was  made  after  the  calves  had  fully  recovered  from  the 
effects  of  the  first,  which  required  from  four  to  six  weeks.  After  the  first  vaccina- 
tion there  was  an  increase  of  temperature  to  40-41°  C.,  which  continued  for  several 
days,  and  following  this  a  high  normal  temperature  was  observed  for  about  two 
weeks,  during  which  time  there  was  either  a  marked  gain  or  loss  in  weight.  After 
this  the  temperature  subsided  and  the  animals  recovered  so  completely  that  the 
second  vaccination  was  made  without  hesitation.  The  second  vaccination  was  fol- 
lowed by  an  immediate  rise  in  temperature,  which  lasted  only  a  few  days  and  did 
not  disturb  the  general  condition  of  the  animals. 

In  order  to  test  the  immunity  the  calves  were  inoculated  intravenously  with  2  cen- 
tigrams of  virulent  bovine  culture,  which  was  so  active  that  one-fortieth  of  this  dose 
was  sufficient  to  produce  a  fatal  case  of  acute  miliary  tuberculosis  in  a  calf  within 
twnty  to  thirty  days.  This  test  is  referred  to  in  the  table  as  the  control  injection. 

The  table  follows: 

Principal  facts  relative  to  recent  immunization  experiments  reported  by  Koch,  Schutz, 

Neufeld,  and  Mieszner. 


No. 
of 
calf. 

Weight 
of  calf. 

Kind  of 
bacillus 
injected. 

Dose 
first  in- 
jection. 

Days 
be- 
tween 
first 
and 
second 
injec- 
tions. 

Dose 
second 
injec- 
tion. 

Days 
be- 
tween 
second 
and 
control 
injec- 
tions. 

Days 
be- 
tween 
con- 
trol in- 
jection 
and 
death 
or  end 
of  test. 

Gain  in 
weight 
during 
experi- 
ment. 

Result  of  final  exami- 
nation. 

1 
2 

Pounds. 
359.7 
353.1 

Human... 
do. 

Centi* 
grams. 
2 
1 

27 
27 

Centi- 
grams. 
5 
5 

42 
42 

100 
96 

Pounds. 
166.1 
39.  G 

Healthy. 
Lung  tuberculosis. 

3 

4 
6 
6 

326.7 

449.9 
346.5 
260.7 

do.... 

...do... 
do.... 
..  .do  

2 

1 

2 
1 

26 

26 
32 
33 

5 

5 
5 
5 

42 

42 
37 
36 

100 

98 
100 
30 

249.7 

159.5 
141.9 

58.3 

Tuberculosis  of  serous 
membranes  and  kid- 
neys. 
Do. 
Healthy. 
Miliary  tuberculosis. 

7 

376.2 

do  

2 

34 

5 

93 

246 

470.8 

Still  alive. 

g 

289  3 

do 

1 

30 

5 

93 

236 

529  1 

Healthy. 

9 

354.2 

...  do     . 

2 

49 

5 

90 

221 

371.8 

Do. 

10 

11 

309.1 
330  0 

do.... 
do 

1 
2 

49 
50 

6 
5 

90 
90 

221 
220 

427.  9 
451.  0 

Still  alive. 
Do. 

12 

321  2 

do     . 

1 

63 

5 

88 

209 

272.8 

Healthy. 

13 

14 
16 

338.8 

290.4 
220.0 

do.... 

...do... 
do  

1 

1 
2 

52 

44 
64 

5 

5 
6 

88 

88 
91 

209 

209 
194 

178.2 

215.6 
308.0 

A  tubercular  focus  the 
size  of  a  hazelnut  in 
the  lung. 
Healthy.. 
Tubercular  foci  in  the 

16 
17 
18 
21 

270.6 
220.0 
264.0 
250.8 

do.... 
do.... 
do.... 
do.... 

„    1 
2 
1 
3 

54 
39 
39 
103 

5 
6 
5 

91 
87 
87 

194 
184 
19-1 
117 

422.4 
316.8 

:;pj.  l 
217.8 

lungs. 
Still  alive. 
Healthv. 
Still  alive. 
Pleuritis  and  peritoni- 

22 

297.0 

...do... 

2 

103 

127 

323.4 

tis  villosa. 
Pleuritis  villosa. 

23 

235.4 

do  

1 

103 

119 

256.2 

Healthy. 

24 

325.6 

Bovine  . 

2 

169 

91 

473.0 

Still  alive. 

25 

228.8 

.....do  

1 

169 

91 

310.2 

Pleuritis  chronica  vil- 

26 

321.2 

do  

1 

21 

91 

354.2 

losa,   bronchitis  and 
peribronchitis   ca- 
tarrhalis  chronica  lo- 
bularis. 
Bronchitis    catarrhalis 

lobularis. 

Each  two  calves,  from  No.  1  to  No.  18,  inclusive,  were  vaccinated  with  human 
bacilli  of  a  different  stock  and  consequently  calves  1  and  2  constitute  one  experi- 
ment, calves  3  and  4  a  second  experiment,  and  so  on.  With  calves  1  to  6  the  period 
between  the  last  vaccination  with  human  bacilli  and  the  control  inoculation  was 
about  forty  days,  and  this  the  authors  think  was  too  short  and  partly  accounts  for 
these  experiments  being  less  successful  than  the  others.  They  also  express  the 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  69 

opinion  from  the  results  of  the  experiments  with  calves  1  and  2  and  5  and  6  that  2 
centigrams  of  culture  for  the  first  vaccination  causes  a  more  rapid  development 
of  immunity  and  makes  this  immunity  more  perfect  than  does  1  centigram.  There 
was  very  little  difference  between  calves  3  and  4;  both  developed  tuberculosis  with 
lesions  of  the  same  character.  Contrasting  strongly  with  the  above  animals  are  the 
calves  from  7  to  18,  inclusive,  which  were  not  inoculated  with  virulent  bovine 
bacilli  until  three  months  had  elapsed  after  the  last  vaccination  with  human  bacilli. 
All  of  these  animals  remained  healthy  with  the  exception  of  two,  which  showed 
comparatively  insignificant  remains  of  old  tubercular  lesions.  The  only  symptom 
which  these  animals  presented  was  slight  fever,  lasting  from  three  to  five  davs. 
They  developed  well  and  increased  in  weight.  Seven  of  the  calves  had  been  dis- 
sected after  being  held  about  a  year,  and  with  calves  8,  9,  12,  14,  and  17  not  the 
slightest  appearance  of  tuberculosis  was  discovered  by  very  careful  examination.  It 
was  only  with  calves  13  and  15  that  such  appearances  were  seen,  and  these  were  of 
old  standing  and  probably  recovered  cases.  The  five  calves  still  living,  Nos.  7,  10, 
11,  16,  and  18,  are  in  excellent  condition  and  free  from  any  appearance  which  would 
lead  one  to  suspect  the  existence  of  tuberculosis. 

These  investigators  conclude  that  by  the  use  of  human  tubercle  bacilli  in  the  man- 
ner described  by  them  a  high  degree  of  immunity  may  be  produced  in  cattle,  but 
that  a  considerable  time  elapses  before  this  immunity  develops  to  the  highest  point 
and  that  the  dose  of  the  culture  used  in  the  first  vaccination  has  a  notable  influence 
upon  the  rapidity  with  which  the  immunity  is  acquired.  All  of  the  stocks  of  bacilli 
used  by  them  were  capable  of  producing  immunity,  the  only  difference  being  that 
some  of  the  stocks  affected  the  calves  more  seriously  than  did  others,  and  young 
cultures  produced  fever  of  longer  duration  than  older  cultures.  The  attenuated 
bovine  bacillus,  which  was  of  slight  virulence  for  cattle,  produced  immunity  in  the 
same  manner  as  the  human  bacillus. 

The  animals  above  referred  to,  Nos.  1  to  18,  were  immunized  by  two  vaccinations 
with  bacilli  of  human  tuberculosis.  The  second  vaccination,  however,  had  produced 
only  a  slight  reaction  and  this  led  the  investigators  to  believe  that  perhaps  a  single 
vaccination  with  a  proper  dose  of  human  tubercle  bacilli  might  cause  with  cattle  a 
sufficient  degree  of  immunity.  In  order  to  test  this  question  the  investigators  chose 
a  culture  for  the  vaccination  which  in  former  tests  had  produced  a  moderately  strong 
reaction,  and  vaccinated  by  intravenous  injection  calf  21  with  3  centigrams,  calf  22 
with  2  centigrams,  and  calf  23  with  1  centigram  of  a  thirty-day  culture.  The  general 
condition  of  the  animals  was  not  disturbed,  and  one  hundred  and  three  days  later 
their  immunity  was  tested  by  the  injection  of  2  centigrams  of  a  culture  of  virulent 
bovine  tubercle  bacilli.  Following  this  inoculation  the  animals  had  fever  of  several 
days'  duration,  and  after  its  subsidence  appeared  entirely  healthy.  After  a  period 
of  one  hundred  and  seventeen  to  one  hundred  and  twenty-seven  days  the  three  ani- 
mals were  all  killed  and  examined,  and  proved  to  be  entirely  free  from  tuberculosis. 
These  three  calves  had  therefore  developed  a  very  high  degree  of  immunity  from  a 
single  vaccination  with  1,  2,  and  3  centigrams  of  the  bacilli  of  human  tuberculosis. 

A  similar  result  was  obtained  with  calves  24  and  25,  which  were  vaccinated  intra- 
venously with  2  centigrams  and  1  centigram,  respectively,  of  an  attenuated  stock  of 
bovine  bacilli,  and  one  hundred  and  sixty-nine  days  later  were  tested  by  inoculation 
with  the  very  virulent  bovine  bacillus.  Calf  24,  which  had  remained  in  an  excellent 
condition,  was  still  living.  Calf  25  was  killed  and  examined  the  two  hundred  and 
sixtieth  day  of  the  experiment,  and,  although  affected  with  pleuritis  chronica  villosa, 
bronchitis,  and  peribronchitis  catarrhalis  chronica  lobularis,  no  tubercle  bacilli  could 
be  found. 

The  authors  conclude  that  they  have  succeeded  by  a  single  vaccination  with  1  to  3 
centigrams  of  bacilli  of  human  tuberculosis  or  of  attenuated  bacilli  of  bovine  tuber- 
culosis in  producing  in  cattle  an  immunity  against  highly  virulent  bacilli  of  bovine 
tuberculosis.  The  bacilli  as  used  up  to  this  time  and  grown  upon  glycerin  bouillon 
must  be  from  30  to  40  days  old.  They  are  dried  between  blotting  paper,  and  the 
required  amount  is  mixed  with  10  c.  c.  of  physiological  salt  solution  and  injected 
into  the  veins. 

VALLEE'S  EXPKRIMENTS. 

On  the  initiative  of  M.  Rossignol,  and  under  the  auspices  of  the 
Societe  de  Medecine  Veterinaire  Pratique,  there  was  begun  at  Melun, 
in  December,  1904,  a  series  of  experiments60  on  the  antituberculous 
vaccination  of  young  cattle  by  the  method  of  Professor  Von  Behring, 
of  Marburg. 


70  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

These  experiments,  which  were  conducted  under  the  direction  of 
Professor  Vallee,  had  for  their  object — 

(1)  To  demonstrate  the  innocuousness  of  the  method  of  vaccination. 

(2)  To  verify  the  efficaciousness  of  the  method. 

(3)  To  establish  its  practical  value  and  in  particular  the  duration  of 
the  immunity. 

December  5,  21  calves  4  to  6  months  old  were  tested  with  tuberculin  without  react- 
ing, and  were  held  in  places  free  from  all  contamination  other  than  was  received  in 
the  experiments. 

December  11,  they  were  given  the  first  vaccine  in  the  jugular. 

About  two  months  later  one  of  the  treated  animals  was  attacked  with  "maladie 
des  pulpes"  and  died.  Its  organs,  examined  by  MM.  Moussu  and  Vallee,  revealed 
no  indication  of  the  existence  of  tuberculosis.  The  other  animals  remained  in  per- 
fect health  and  showed  normal  development. 

February  13,  the  20  surviving  animals  were  tested  with  tuberculin.  Four  animals 
reacted  clearly,  with  regard  to  which  Professor  Vallee  remarked  that  the  reaction 
was  no  cause  for  anxiety  or  surprise,  as  the  inoculated  bacilli  could  not  be  absorbed 
without  causing  the  formation  of  micrpscopic  lesions  sufficient  to  cause  a  reaction. 

March  12,  three  months  after  the  first  vaccination,  the  20  animals  received  the 
second  vaccine. 

At  the  beginning  of  June  all  vaccinated  animals  were  tested  with  tuberculin. 
Only  1  animal  reacted,  and  this  failed  to  react  to  subsequent  tests.  This  and  4 
other  vaccinated  animals  were  put  in  a  lot  together  with  the  object  of  testing  the. 
duration  of  the  immunity. 

June  15,  the  15  vaccinated  animals  remaining  were  tested  as  follows:  Six  received 
4£  milligrams  each  of  a  fresh  culture  of  very  virulent  bovine  bacilli;  7  were  inocu- 
lated subcutaneously,  and  2  were  exposed  by  cohabitation  with  tuberculous  bovine 
animals.  Check  animals  which- did  not  react  to  tuberculin  and  equal  in  number  to 
the  vaccinated  ones  were  submitted  to  the  same  test. 

Very  soon  a  number  of  the  check  animals  showed  very  marked  symptoms,  and  3 
of  those  inoculated  intravenously  died  in  thirty  to  forty  days. 

The  following  is  a  brief  resume  of  the  results  of  these  tests: 

A.  INTRAVENOUS  TESTS. — (1)  Checks. — Three  died  with  considerable   pulmonary 
lesions  thirty  to  forty  days  after  the  inoculation.     The  3  surviving  ones  showed  on 
autopsy  extensive  and  generalized  lesions. 

(2)  Vaccinated  animals. — Five  were  absolutely  immune.  The  sixth,  affected  with 
pasteurell»sis  at  the  time  of  the  test  inoculation,  and  consequently  having  less  resist- 
ance, presented  five  or  six  disseminated  tubercles  in  the  bronchial  and  mediastinal 
glands,  but  no  visceral  lesions. 

B.  SUBCUTANEOUS  TESTS. — (1)  Checks. — Three  showed  enormous  lesions  of  the  cor- 
responding prescapular  gland.     Four  had  in  addition  generalized  lesions  of  the  lungs 
and  of  the  bronchial  and  mediastinal  glands. 

(£)  Vaccinated  animals. — With  5  of  these  no  lesions  were  discovered  in  the  glands 
nearest  to  the  point  of  inoculation.  With  another  there  was  found  a  tubercle  in  the 
prescapular  gland.  The  seventh  had  an  extensive  tuberculous  adenitis  of  this  gland. 

C.  TESTS  BY  COHABITATION. — (1)  Checks. — These  had  generalized  tuberculosis  fol- 
lowing an  infection  from  the  digestive  tract,  as  was  proved  by  the  lesions  observed. 

(2)  Vaccinated  animals. — These  did  not  react  to  the  tuberculin  test  and  were  pre- 
served and  left  in  contact  with  tuberculous  animals. 

CONCLUSIONS. — This  method  of  vaccination  appeared  free  from  danger  because  none 
of  the  vaccinated  animals  reacted  to  tuberculin  a  few  months  after  the  second  vac- 
cination. As  to  the  efficaciousness  of  the  vaccination,  it  was  shown  that  5  out  of  6 
of  the  vaccinated  animals  developed  no  lesions  when  tested  by  intravenous  inocula- 
tion, whereas  the  checks  died  or  became  tuberculous;  5  of  the  7  tested  by  subcu- 
taneous inoculation  were  immune,  whereas  the  checks  all  had  extensive  lesions  in 
the  neighboring  glands  and  several  had  generalized  lesions  in  the  lungs  and  annexed 
glands;  and,  finally,  all  of  the  vaccinated  animals  successfully  resisted  the  test  by 
cohabitation,  which  is  the  usual  method  of  infection,  whereas  the  check  animals  all 
became  tuberculous. 

Vallee  concludes  that  it  is  experimentally  possible  to  confer  on  young  bovine  ani- 
mals a  high  degree  of  immunity  in  regard  to  tuberculosis.  The  duration  of  the 
immunity  is  being  tested  by  further  observation. 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  71 

CONCLUSIONS   REGARDING   IMMUNIZATION. 

It  is  evident  from  the  investigations  which  have  just  been  reviewed 
that  great  progress  has  been  made  in  the  development  of  a  method  for 
immunizing  cattle  against  tuberculosis.  The  results  of  the  different 
tests  up  to  this  time  have  not  been  as  uniform  as  is  desirable,  but  they 
are  constantly  improving  in  this  respect,  and  there  is  good  reason  to 
expect  that  a  safe  and  effective  method  will  soon  be  available.  At  pres- 
ent there  is  considerable  uncertainty  as  to  the  period  of  time  during 
which  the  efficacy  of  the  "vaccine"  remains  unimpaired,  as  to  the 
proper  degree  of  virulence  for  the  vaccine  and  the  number  of  doses 
required  for  protection  against  natural  infection,  and  also  as  to  the 
duration  of  the  immunity. 

The  danger  to  the  operator  from  using  dry  and  powdered  human 
tubercle  bacilli  as  vaccine  has  been  mentioned  by  several  investigators 
and  should  receive  serious  consideration.  The  liquid  form  appears  to 
be  more  efficacious  and  more  simple  in  its  manipulation.  The  dry 
vaccine  is  said  to  retain  its  properties  unimpaired  for  a  month,  but 
considering  the  time  required  to  put  it  in  packages  and  ship  it  from 
Germany  to  the  United  States,  it  is  to  be  feared  that  in  many  cases 
much  more  than  a  month  would  elapse  between  its  preparation  and  its 
injection  into  American  cattle. 

This  method  of  protecting  cattle  from  tuberculosis  i.s  still  so  new, 
and  has  been  used  so  little  under  practical  conditions,  that  it  should 
only  be  adopted  by  the  cattle  owner  with  much  caution  and  under 
expert  veterinary  supervision.  The  danger  of  adopting  hasty  conclu- 
sions as  to  the  degree  of  immunity  conferred  upon  cattle  by  inoculation 
with  tubercle  bacilli  has  been  shown  by  some  of  the  experiments  which 
have  been  mentioned  in  preceding  pages.  There  is  still  much  to  learn 
about  these  "vaccines"  and  their  effects,  and  the  owner  of  cattle  will 
be  wise  to  avoid  their  use  pending  further  investigations,  except  in 
the  most  urgent  cases  and  under  conditions  where  such  treatment  is 
clearly  indicated. 

THE  CURATIVE  EFFECT  OF  TREATMENT  WITH  TUBERCULIN 
AND  WITH  ATTENUATED  TUBERCLE  BACILLI. 

Pearson  and  Gilliland"3  have  published  a  report  of  some  experiments 
made  by  them  to  test  the  effect  of  treatment  with  tuberculin  and  with 
tubercle  bacilli  of  the  human  type  upon  young  cattle  which  had 
reacted  to  tuberculin  and  which  were  presumably  affected  with  tuber- 
culosis in  its  early  stages.  In  testing  with  tuberculin  a  large  herd  of 
Shorthorn  and  grade  Shorthorn  cattle  in  December,  1902,  it  was  found 
that  practially  all  of  the  members  of  the  herd  responded  to  the  test. 
Among  the  animals  so  responding  were  12  calves  from  6  to  8  months 
of  age.  These  calves  were  obtained  for  use  in  this  experiment  and 
were  again  tested  February  2-3,  1903.  All  responded  to  the  test. 


72  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

They  were  then  weighed  and  divided  into  two  lots  of  6  each,  as  nearly 
equal  in  respect  to  size,  weight,  age,  and  condition  as  possible.  One 
of  these  lots  was  subdivided  into  two  groups  of  3  each. 

The  calves  of  one  of  these  subgroups  were  given  7  intravenous  injections  of  a 
standard  suspension  in  water  of  tubercle  bacilli  of  human  type.  The  dosage  l>egan 
at  1  c.  c.  and  was  increased  to  6  c.  c.  The  intervals  were  six  to  twenty  days,  and  the 
period  covered  was  from  February  9  to  May  1,  1903.  A  final  injection  was  given 
about  a  year  later,  March  29,  1904. 

The  3  calves  of  the  second  subgroup  were  given  subcutaneous  injections  of  tuber- 
culin at  intervals  of  from  one  to  ten  days.  The  injections  of  tuberculin  were 
repeated  until  the  hypersensitiveness  of  the  animal  to  tuberculin  had  disappeared, 
after  which  the  calves  received  an  intravenous  injection  of  a  suspension  of  tubercle 
bacilli  in  water.  Following  each  intravenous  injection  of  living  tubercle  bacilli  the 
animal  was  given  tuberculin  a  number  of  times  until  its  hypersensitiveness  to  tuber- 
culin again  disappeared.  The  period  of  treatment  extended  from  February  9  to 
April  30,  1903,  inclusive,  and  the  calves  of  this  group,  as  of  the  group  first  described, 
were  given  an  intervaneous  injection  of  5  c.  c.  of  standard  suspension  of  living 
tubercle  bacilli  March  29,  1904.  Following  this,  tuberculin  was  administered  five 
times  at  intervals  of  three  or  four  days. 

The  remaining  6  calves  were  given  no  treatment  whatever,  but  were  at  all  times 
kept  with  the  6  calves  under  treatment,  so  that  all  of  the  12  calves  in  this  experiment 
were  subjected  to  the  same  conditions  of  life  and  subsisted  upon  the  same  kind  and 
quantity  of  food. 

Two  cattle,  both  controls,  died;  the  first  one  May  5,  1903,  the  second  September 
13,  1904;  two — 1  control  and  1  treated — were  killed  April  4,  1904,  and  the  rest  were 
killed  in  September,  1904.  All  were  submitted  to  careful  post-mortem  examination. 

The  calves  of  the  first  group  had  from  one  to  three  small  tubercular  lesions  each, 
which  were  the  size  of  a  pea  or  less.  In  the  case  of  one  calf  only  was  one  of  these 
found  in  the  lung;  in  the  others  they  were  confined  to  the  lymphatic  glands.  The 
calves  of  the  second  group  had  still  smaller  and  more  insignificant  lesions,  confined 
in  all  cases  to  the  bronchial  glands.  In  both  of  these  groups  of  animals  the  lesions 
were  quiescent,  encapsulated,  and  some  of  them  calcareous.  The  calves  of  the  third 
group,  which  received  no  preventive  treatment,  were  affected  in  a  much  more  serious 
manner.  In  4  of  the  6  the  lungs  were  quite  extensively  diseased;  in  2  only  were  the 
tubercular  changes  confined  to  the  lymphatic  glands.  One  of  the  animals  presented 
a  case  of  "pearl  disease"  in  its  most  advanced  form  and  widest  distribution.  There 
was  consequently  a  decided  difference  between  the  6  young  cattle  that  were  treated 
and  the  6  that  were  not  treated;  and  since  the  two  lots  of  animals  were  comparable 
in  every  way,  excepting  in  respect  to  the  specific  treatment,  it  appears  reasonable  to 
conclude  that  the  treated  animals  were  favorably  influenced  by  the  treatment.  Not 
only  does  the  disease  appear  to  have  been  held  in  check  by  the  treatment,  but  there 
was  reason  to  believe  that  in  some  of  the  animals  it  had  a  decided  curative  effect. 

In  all  of  the  treated  animals  the  lesions  were  quiescent  and  encapsulated,  but  they 
nevertheless  contained  living  tubercle  bacilli  which  were  capable  of  causing  the  dis- 
ease in  guinea  pigs.  The  investigators  remarked  with  reason  that  these  experiments 
which  were  made  on  a  few  young  cattle  in  the  earlier  stage  of  tuberculosis  do  not 
justify  conclusions  or  inferences  as  to  the  probable  effect  of  similar  treatment  on 
older  and  more  extensively  diseased  animals. 

These  experiments  confirm  the  results  of  experiments  by  various 
investigators  as  to  the  production  of  immunity  by  the  treatment  of 
cattle  with  tuberculin  and  cultures  of  human  and  other  tubercle  bacilli 
nonvirulent  for  these  animals.  As  to  whether  it  will  be  advisable  to 
administer  such  treatment  to  diseased  young  cattle  in  general  practice 
must  be  considered  doubtful,  in  view  of  the  fact  that  the  diseased  areas 
continue  to  harbor  virulent  living  bacilli  for  a  long  time  after  the  treat- 
ment has  been  concluded.  Further  studies  of  this  subject  must  be 
made  before  positive  recommendations  can  be  offered;  but  even  with 
doubt  on  this  point,  the  experiments  have  much  value  as  indicating 
how  complete  a  degree  of  immunity  may  be  developed  by  proper 
treatment. 


MATERIAL    FACTS    CONCERNING   TUBERCULOSIS.  73 

ANIMAL  TUBERCULOSIS  AND  THE  PUBLIC  HEALTH. 

EARLY   VIEWS. 

There  has  been  much  difference  of  opinion  as  to  the  effect  of  animal 
tuberculosis  upon  the  public  health,  and  curiously  enough  the  weight 
of  numbers  appears  to  have  been  with  those  who  believed  that  there 
was  little  if  any  danger  to  be  apprehended  from  this  source.  There 
were  local  laws  in  Munich  more  than  five  hundred  j^ears  ago  which 
prohibited  the  use  of  the  flesh  of  animals  affected  with  bovine  tuber- 
culosis, and  similar  ordinances  were  subsequently  enacted  in  various 
German  cities.  There  appears,  however,  to  have  been  no  great  effort 
to  enforce  these  ordinances,  or,  at  most,  they  were  only  enforced  spas- 
modically, until  in  the  early  part  of  the  eighteenth  century,  when  the 
opinion  became  prevalent  that  tuberculosis  and  syphilis  were  identical. 
While  this  idea  was  dominant  the  regulations  concerning  the  sale  of 
the  meat  of  tuberculous  animals  were  more  stringent!}'  enforced. 

In  1783,  however,  the  health  authorities  of  Berlin  promulgated  an 
opinion  to  the  effect  that  tuberculosis  and  syphilis  were  different  and 
distinct  diseases,  and  permitted  the  sale  of  the  carcasses  of  tuberculous 
animals  for  human  food.  This  view  appears  to  have  been  accepted  by 
other  German  States  and  by  Austria,  and  for  a  third  of  a  centuiy 
such  meat  was  sold  without  question.  The  ideas  in  regard  to  tuber- 
culosis were  vague  and  erroneous,  and  it  was  not  until  1811  that 
Laennec  proclaimed  the  unity  of  the  different  forms  of  tuberculous 
lesions.  His  views  were  vigorously  contested,  but  they  nevertheless 
made  a  strong  impression  upon  the  medical  thought  of  the  earty  part 
of  the  nineteenth  centuiy.  Within  a  fe\v  years  regulations  were 
formulated  in  different  places  for  the  guidance  of  meat  inspectors  in 
judging  the  carcasses  of  tubercular  animals.  Gurlt  (1831)  recognized 
the  tubercular  nature  of  the  "  pearl  disease"  of  cows. 

About  1850  German  histologists  contested  the  views  of  Laennec  and 
denied  any  relationship  between  human  and  bovine  tuberculosis. 
Reinhard,  Virchow,  and  Niemeyer  recognized  a  true  tuberculosis 
characterized  by  the  "  gray  granulation,"  and  a  caseous  pneumonia 
resulting  from  postinflammatory  degeneration  (Nocard).  However, 
Gerlach,  Spinola,  Fuchs,  Forster,  Leisering,  and  others  declined  to 
accept  such  views  and  produced  observations  to  show  the  tuberculous 
nature  of  the  "pearl  disease"  of  cattle. 

In  1866  Villemin  introduced  a  new  epoch  in  the  discussion  of  ques- 
tions relating  to  the  nature  of  this  disease  by  demonstrating  the  inocu- 
lability  of  tuberculosis  not  only  from  animal  to  animal  within  the 
same  species,  but  from  an  animal  of  one  species  to  an  animal  of  an 
entirely  different  species,  and  even  from  man  to  animals. 

Villemin's  conclusions  were  soon  confirmed  by  the  results  of  experi- 
ments made  by  Chauveau,  Gerlach,  Gfinther  and  Harms,  and  other 
experimenters.  As  late  as  1880,  however,  Virchow  insisted  at  length  that 


74  TUBERCULOSIS    OF    THE    FOOD-PRODUCING    ANIMALS. 

essential  anatomic  and  pathologic  differences  separated  the  tubercles  of 
the  pearl  disease  of  cattle  from  those  of  consumption  in  man,  and  held 
that  the  existence  of  a  virus  in  pearl  disease  had  not  been  demonstrated. 
It  required  another  epoch-making  discovery,  that  of  the  Bacillus 
tuberculosis  b\r  Koch,  in  1882,  to  convince  the  medical  world  that  tuber- 
culosis was  a  communicable  disease,  and  that  an  identical  bacillus  was 
found  in  the  tubercles  of  man  and  many  different  species  of  animals. 
This  discovery  again  attracted  attention  to  the  danger  which  might  be 
connected  with  the  tuberculosis  of  animals  and  led  to  more  rigid 
enforcement  of  regulations  to  guard  against  any  dangers  which  might 
threaten  the  public  health  through  the  sale  of  meat  and  milk  from 
tubercular  animals. 

IDENTITY   OF    HUMAN    AND   BOVINE    TUBERCULOSIS   QUESTIONED. 

Years  passed,  and  it  appeared  to  be  definitely  established  that  human 
and  animal  tuberculosis  were  identical,  when  Theobald  Smith  published 
(1898)  the  results  of  a  comparative  study  of  bovine  tubercle  bacilli 
and  of  human  bacilli  from  sputum,  in  which  it  was  shown  that  the 
bacilli  from  these  two  sources  differed  to  such  an  extent  that  they 
might  be  considered  as  distinct  types.  Not  only  was  there  a  great 
difference  in  the  virulence  of  bacilli  from  the  two  sources,  but  there 
were  marked  morphological  and  cultural  differences  shown  by  the 
bacilli..  These  conclusions  were  soon  confirmed  by  Dinwiddie  and  by 
Frothingham. 

The  observations  were,  not  entirely  new,  however,  as  Sidney  Martin, 
in  his  experiments  for  the  British  Royal  Tuberculosis  Commission  of 
1895,  had  shown  that  sputum  from  man  was  far  less  virulent  for  ani- 
mals than  was  bovine  tubercular  material.  It  could  not  be  said  from 
these  experiments  that  human  tuberculosis  was  not  communicable  to 
cattle,  but  only  that  it  was  communicated  with  difficulty,  and  when  it 
was  communicated  the  disease  remained  localized  and  did  not  result 
fatally.  Of  6  calves  to  which  sputum  was  fed  by  Martin,  2  showed  no 
lesions,  1  had  53,  1  had  63,  and  2  each  had  13  tubercular  nodules  in  the 
intestines.  In  one  of  these  animals  the  mesenteric  glands  were  also 
affected.  In  Smith's  experiments  there  were  also  small  lesions  in  some 
of  the  animals  with  which  he  experimented. 

In  an  address  before  the  British  Congress  on  Tuberculosis,  held  in 
London  in  1901,  Koch  expressed  very  radical  views  as  to  the  difference 
between  human  and  bovine  tuberculosis.  He  held  (1)  that  human 
tuberculosis  differs  from  bovine,  and  can  not  be  transmitted  to  cattle; 
(2)  that  while  the  susceptibility  of  man  to  bovine  tuberculosis  was  not 
yet  absolutely  decided,  he  was  nevertheless  at  liberty  to  say  that  if 
such  a  susceptibility  really  exists  the  infection  of  human  beings  is  but 
a  very  rare  occurrence.  He  estimated  the  extent  of  infection  by  the 
milk  and  flesh  of  tubercular  cattle,  and  the  butter  made  of  their  milk, 
as  hardly  greater  than  that  of  hcreditaiy  transmission,  and  he  there- 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  75 

fore  did  not  deem  it  advisable  to  take  any  measures  against  it.  He 
held  that  it  was  now  possible  to  determine  whether  tubercular  disease 
in  the  human  subject  was  of  human  or  animal  origin.  He  said: 

All  that  is  necessary  is  to  cultivate  in  pure  culture  the  tubercle  bacilli  found  in  the 
tubercular  material,  and  to  ascertain  whether  they  belong  to  bovine  tuberculosis  by 
inoculating  cattle  with  them.  For  this  purpose  I  recommend  subcutaneous  injection, 
which  yields  quite  specially  characteristic  and  convincing  results. 

This  unexpected  announcement  by  so  great  an  authority  aroused 
great  interest  and  led  to  tremendous  activity  among  investigators  in 
all  parts  of  the  world.  As  a  result  of  the  problem  being  attacked  by 
many  individuals  and  from  different  points  of  view  the  principal  facts 
have  already  been  ascertained  and  established. 

INVESTIGATIONS   BY   THE   GERMAN    COMMISSION. 

Koch  announced  in  his  London  address  that  the  German  Govern- 
ment had  already  appointed  a  commission  to  make  further  inquiries 
on  the  subject.  A  preliminary  report  was  made  from  this  commission 
by  Kossel  in  1903.  At  that  time  the  commission  had  tested  7  cultures 
of  tuberculosis  from  cattle  and  hogs — 4  from  cattle  and  3  from  hogs. 
Two  of  these  cultures  proved  acutely  fatal  to  cattle  after  eight  to  nine 
weeks.  Four  of  the  cultures  likewise  produced  a  generalized  tuber- 
culosis, but  which  certainly  had  a  more  chronic  course,  while  1  of 
the  cultures  caused  only  an  infiltration  at  the  point  of  inoculation, 
with  some  caseous  foci  in  the  adjoining  prescapular  gland  and  in  one 
of  the  mediastinal  glands,  and  there  was  lacking  the  spreading  of 
tuberculosis  over  the  entire  body,  which  they  were  accustomed  to  see 
after  the  injection  of  cultures  of  bovine  tuberculosis.  "Hence,"  said 
Kossel,  "among  bovine  tuberculosis  bacilli  there  can  also  occur  dif- 
ferences with  regard  to  the  virulence." 

The  commission  had  also  tested  39  different  freshly  made  cultures 
from  tuberculous  disease  in  man.  Nineteen  of  these  cultures  did  not 
produce  the  slightest  symptoms  in  cattle;  with  9  others  the  cattle 
exhibited,  after  four  months,  very  minute  foci  in  the  prescapular 
glands,  which  were  mostly  encapsuled  and  showed  no  inclination  to 
progress;  with  7  others  there  was  somewhat  more  marked  disease  of 
the  prescapular  glands,  but  it  did  not  go  so  far  as  a  material  spread- 
ing of  the  process  to  the  glands  next  adjoining.  There  were  4  cul- 
tures, however,  which  were  more  virulent  and  caused  generalized 
tuberculosis  in  the  cattle  inoculated  with  them. 

It  was  therefore  evident  that,  contrary  to  Koch's  assertion,  it  was 
not  always  possible  to  determine  whether  a  culture  of  the  tuberculosis 
bacillus  originated  in  man  or  in  cattle  by  inoculating  it  subcutaneously 
in  bovine  animals.  One  of  the  bovine  cultures  failed  to  produce  gen- 
eralized tuberculosis  in  cattle,  which  according  to  Koch's  contention 
it  should  have  done;  and  4  of  the  human  cultures  did  produce  this 
form  of  disease,  which  according  to  the  same  authority  they  should 
not  have  done.  Moreover,  while  some  of  the  human  cultures  caused 


6  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

no  disease  at  all,  others  led  to  the  development  of  minute  foci  in  the 
prescapular  glands,  and  still  others  to  somewhat  more  marked  disease 
of  these  glands.  There  were,  consequently,  four  degrees  of  virulence 
noted  in  these  39  cultures  from  human  sources,  and  three  degrees  of 
virulence  in  the  7  cultures  from  animal  sources. 

It  was  definitely  admitted  that  4  of  the  human  cultures  caused  gen- 
eralized tuberculosis  in  cattle;  but  it  was  suggested  by  Kossel  that  it 
might  be  possible  that  the  bacilli  in  cases  of  human  tuberculosis  under 
certain  circumstances  could  likewise  attain  a  very  high  degree  of 
pathogenic  activity  for  cattle  without  being  for  that  reason  bovine 
bacilli.  The  German  commission  was  confronted  by  the  two  horns  of 
a  dilemma,  either  one  of  which  was  fatal  to  the  views  of  Koch  as 
stated  with  great  positiveness  at  London.  If  the  suggestion  thrown 
out  by  Kossel  was  adopted  it  was  necessary  to  conclude  that  Koch  was 
wrong  in  his  claim  that  human  tuberculosis  can  not  be  transmitted  to 
cattle,  and  thus  with  one  stroke  of  the  pen  the  commission  would 
destroy  the  entire  experimental  support  which  he  had  for  his  argument 
before  the  British  Congress  on  Tuberculosis.  If,  on  the  other  hand, 
it  accepted  the  conclusion  which  followed  from  the  principle  laid  down 
by  Koch  for  discriminating  between  human  and  bovine  bacilli,  it  was 
necessary  to  admit  that  bovine  tuberculosis  is  an  extremely  important 
factor  in  the  etiology  of  human  tuberculosis.  Of  the  39  cases  of 
human  tuberculosis  tested,  4,  or  over  10  per  cent,  were  virulent  for 
cattle  and  would  be  classified  as  of  bovine  origin;  but  these  4  cases 
were  all  found  among  the  16  cases  of  tuberculosis  in  children  which 
the  commission  investigated;  and,  therefore,  25  per  cent  of  the  cases 
tested  of  tuberculosis  in  children  should  by  Koch's  method  be  classified 
as  of  bovine  tuberculosis. 

These  results  were  in  accordance  with  researches  made  by  other 
investigators.  De  Schweinitz,  Mohler,  and  Ravenel  in  this  country 
easily  succeeded  in  obtaining  human  tubercle  bacilli  which  caused 
generalized  tuberculosis  in  cattle,  and  most  of  these  originated  in 
tuberculous  children. 

INVESTIGATIONS   BY    THE   GERMAN   IMPERIAL   HEALTH    OFFICE. 

In  67  cases  of  tuberculosis  in  human  beings  studied  up  to  the  present 
time  in  the  investigations  of  the  German  imperial  health  office,81  and 
which  were  selected  with  the  object  of  finding  as  many  cases  as  pos- 
sible of  the  bovine  type,  there  were  found  in  56  cases  bacilli  of  the 
human  t}rpe  alone,  in  9  cases  bacilli  of  the  bovine  type  alone,  and  in 
2  cases  bacilli  of  both  types  were  found  in  the  same  person.  The  9 
cases  affected  with  bovine  bacilli  alone  were  all  children  under  8  years 
of  age.  Of  the  2  persons  affected  with  bacilli  of  both  types  one  was 
a  woman  30  years  old  and  the  other  a  child  5£  years  old. 

Eleven  cases  of  tuberculosis  in  fowls  were  investigated,  all  of  which 
were  caused  by  the  fowl  tuberculosis  bacillus.  In  11  different  cases 


MATERIAL    FACTS    CONCERNING    TUBERCULOSIS.  77 

of  tuberculosis  in  cattle  there  were  found  exclusively  bacilli  of  the 
bovine  type.  In  7  cases  of  tuberculosis  in  swine  there  were  found 
only  bacilli  of  the  bovine  type.  In  one  case  in  a  3-months-old  pig 
which  had  shown  no  symptons  of  tuberculosis  there  were  found  fowl 
tuberculosis  bacilli  in  the  caseous  mesenteric  glands.  In  one  case  of 
general  tuberculosis  in  a  sheep  there  were  found  tubercle  bacilli  of 
the  bovine  type. 

The  German  imperial  health  office62  has  recently  given  out  the  fol- 
lowing summary  of  the  results  of  the  investigations  relative  to  the 
danger  to  human  health  from  animal  tuberculosis: 

1.  TUBERCULOSIS  OF  DOMESTIC  ANIMALS. — A.  Tuberculosis  of  cattle. — 1.  Bovine  tuber- 
culosis is  caused  by  tubercle  bacilli  of  the  typus  bovinm  (bovine  type).     It  arises 
through  infection  with  tubercle  bacilli  which  have  been  excreted  by  diseased  ani- 
mals suffering  from  certain  forms  of  tuberculosis. 

2.  The  source  for  the  infection  of  cattle  is  almost  exclusively  cattle  which  are  suffer- 
ing from  tuberculosis  of  the  udder,  of  the  intestines,  of  the  uterus,  or  of  the  lungs, 
and  which  excrete  tubercle  bacilli  with  the  milk,  with  the  contents  of  the  intestines, 
with  the  secretions  of  the  uterus,  or  simply  through  the  respiratory  organs. 

3.  The  sickening  of  cattle  is  possible  in  consequence  of  the  reception  of  tubercle 
bacilli  of  the  typus  bovinus  which  have  been  excreted  by  other  diseased  domestic 
mammals  such  as  sheep,  goats,  and  swine  suffering  from  tuberculosis. 

4.  The  tuberculous  human  being,  in  the  rare  cases  in  which  he  excretes  tubercle 
bacilli  of  the  typus  borinvs,  presents  danger  to  cattle. 

5.  The  tuberculosis  of  fowls  seems,  under  ordinary  circumstances,  hardly  to  present 
any  danger  for  cattle. 

6.  In  combating  tuberculosis  in  cattle  the  most  important  thing  is  to  prevent  the 
transference  of  the  germs  of  infection  from  tuberculous  to  sound  cattle. 

B.  Tuberculosis  of  swine. — 1.  In  tuberculous  swine,  tubercle  bacilli  of  the  typus 
bovimis  are  almost  without  exception  the  only  ones  found  in  the  disease  centers. 

2.  Tuberculosis  of  swine  has  its  principal  origin  in  the  tuberculosis  of  cattle,  and 
in  the  second  place  in  the  transference  of  tuberculosis  from  one  hog  to  another.    Nor 
ia  it  impossible  for  the  tuberculosis  of  other  domestic  mammals  and  of  fowls  to  be 
transferred  to  swine. 

3.  The  tuberculous  human  being  can  give  tuberculosis  to  swine,  no  matter  what 
be  the  origin  of  his  own  disease. 

4.  As  source  of  infection,  the  excretions  and  the  flesh  of  diseased  mammals  in  which 
living  tubercle  bacilli  are  contained  come  chiefly  under  consideration.    The  greatest 
danger  comes  from  feeding  swine  with  the  separator  refuse  from  the  dairies. 

C.  Tuberculosis  in  the  other  domestic  mammals. — 1.  The  tuberculosis  of  the  other 
domestic  mammals  is  to  be  traced  back  in  most  cases  to  the  tuberculosis  of  cattle. 

2.  It  is  to  be  expected  that  the  repression  of  the  tuberculosis  of  cattle  will  lead  to 
a  decrease  of  the  tuberculosis  of  swine  and  the  other  domestic  mammals. 

D.  Tuberculosis  in  domestic  birds. — 1.  The  tuberculosis  of  domestic  birds  (fowls, 
pigeons,  ducks,  and  geese)  is  generally  caused  and  spread  by  the  fowl  tuberculosis 
bacillus. 

2.  As  the  principal  source  of  infection  we  must  consider  the  intestinal  excretions 
and  parts  of  the  bodies  of  diseased  birds  which  have  undergone  tubercular  changes. 

II.  TUBERCULOSIS  OF  HUMAN  BEIN<;S. — 1.  In  parts  of  the  human  body  affected  by 
tuberculosis  there  are  generally  found  tubercle  bacilli  of  the  typus  humanus  (human 
type) .  * 

2.  It  must  be  assumed  that  here  the  infection  with  tuberculosis  has  taken  place 
chiefly  through  direct  or  indirect  transference  of  tubercle  bacilli  from  man  to  man. 

3.  Accordingly  the  measures  recommended  for  combating  tuberculosis  are  directed 
principally  against  the  direct  or  indirect  transference  of  the  germ  of  infection  from 
tuberculous  to  healthy  people. 

4.  Besides  this  we  must  reckon  with  the  possibility  that  tubercle  bacilli  of  the 
typus  humanus  may  be  transferred  to  human  beings  through  the  flesh  of  tuberculous 
swine. 

5.  The  fact  that  in  a  number  of  cases  where  organs  of  the  human  body  have  been 
found  to  have  undergone  a  tuberculous  change,  the  presence  of  tubercle  bacilli  of  the 
typus  borinus  has  been  proved,  shows  that  the  human  body  is  capable  of  receiving 
the  germs  of  infection  from  secretions  containing  tubercle  bacilli  (for  exam  pie,  milk) 
or  from  tuberculous  flesh  of  domestic  mammals. 


78  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

6.  The  changes  in  the  tissue  brought  about  in  human  beings  through  tubercle 
bacilli  of  the  typus  bovinus  are  limited  in  a  remarkable  number  of  cases  to  the  passage 
through  which  the  germs  have  found  entrance,  and  to  the  adjac.-nt  glands  or  to  the 
latter  alone.     Nevertheless  tubercle  bacilli  of  the  typus  bovinus  have  also  been  found 
in  cases  where  the  disease  had  spread  from  the  locality  of  entrance  to  distant  parts 
of  the  body  and  had  caused  the  death  of  the  person  in  question. 

7.  The  use  of  food,  therefore,  which  comes  from  tuberculous  animals  and  contains 
living  tubercle  bacilli  of  the  typus  bovinus  is  not  to  be  regarded  as  being  without 
danger  for  the  health  of  human  beings,  especially  when  the  latter  are  children. 

8.  A  conscientiously  conducted  meat  inspection  constitutes  an  important  protection 
against  the  transmission  of  the  tubercle  bacilli  to  human  beings  through  meat;  there 
is  also  protection  afforded  by  the  proper  preparation  of  meat  (thorough  boiling  or 
roasting). 

9.  The  possibility  of  the  transference  of  tubercle  bacilli  through  milk  or  milk 
products  to  the  human  being  may  be  considerably  diminished  by  the  efficient  com- 
bating of  tuberculosis  in  cattle.     The  tubercle  bacilli  contained  in  milk  may  be  killed 
by  heating  the  milk  to  the  necessary  temperature. 

10.  The  tuberculosis  in  poultry  used  for  domestic  purposes  appears  to  play  no  part 
in  the  propagation  of  the  disease  among  human  beings. 

CONCLUSIONS   NOW   GENERALLY   HELD   BY   SCIENTISTS. 

These  statements  fairly  represent  the  condition  of  our  knowledge 
with  reference  to  human  and  animal  tuberculosis,  but  the  conclusion 
should  not  be  reached  from  this  brief  summary  that  the  German 
investigators  are  entitled  to  all  the  credit  for  having  elucidated  this 
perplexing  question.  On  the  contrary,  similar  results  were  announced 
at  an  earlier  date  by  the  investigators  of  other  countries,  and  especially 
by  those  of  Great  Britain,  France,  and  the  United  States. 

The  following  conclusions  are,  therefore,  regarded  as  demonstrated 
by  experimental  investigations  in  which  many  scientists  have  partici- 
pated, and  these  conclusions  are  now  generally  accepted  by  scientific 
men: 

1.  Bovine  tuberculosis  may  be  communicated  to  human  beings,  and 
in  such  cases  it  is  usually  children  that  are  affected. 

2.  Tuberculosis  of  other  domesticated  mammals  (hogs,  sheep,  goats, 
etc.)  may  also  be  communicated  to  human  beings.     It  is  usually,  but 
not  always,  of  the  bovine  type. 

3.  The  tuberculosis  of  poultry  is  not  communicable   to   human 
beings. 

4.  Parrots  and  some  other  varieties  of  cage  birds  may  be  affected 
with  a  t}rpe  of  tuberculosis  communicable  to  human  beings. 

5.  The  tuberculosis  of  human  beings,  as  a  rule,  is  not  communicable 
to  cattle,  but  is  communicable  to  pigs,  dogs,  and  cats.     Thje  bacilli  in 
a  certain  proportion  of  the  cases  of  human  tuberculosis,  however,  are 
virulent  for  cattle  and  produce  in  these  animals  a  fatal  generalized 
tuberculosis. 

6.  Precautions  should  be  taken  to  protect  human  beings  from  animal 
tuberculosis  by  a  careful  inspection  of  meat-producing  animals  at  the 
time  of  slaughter  and  of  the  cows  from  which  milk,  cream,  and  butter 
are  produced. 


PART  II.— THE  REPRESSION  OF  TUBERCULOSIS. 


MEASURES   THAT   MAY   BE   ADOPTED  BY   INDIVIDUALS. 

PREVENTION    Bi'    AVOIDING    KNOWN    CAUSES   OF    TUBERCULOSIS. 

The  first  requisite  for  preventing  tuberculosis  is  to  provide  roomy, 
well  ventilated,  light,  dry,  and  clean  stables  for  the  animals.  Tuber- 
culosis will  not  originate  even  in  dirty  stables  if  the  bacillus  is  not 
introduced  in  some  manner;  but  there  are  so  many  ways  by  which  it 
may  enter  a  stable  that  the  breeder  and  dairyman  should  alwaN's  be 
prepared  for  it.  There  is  much  less  danger  of  the  disease  spreading 
in  a  stable  properly  built  and  maintained  than  in  an  ordinary  stable, 
and  in  case  it  spreads,  its  progress  will  be  much  slower,  and  the 
animals  less  severely  affected. 

There  are  a  few  points  in  the  building  of  a  stable  to  make  it  as  secure 
as  possible  against  tuberculosis  which  should  receive  special  attention. 
It  is  preferable  that  the  floor  should  be  of  concrete.  Wooden  floors 
are  generally  defective  and  allow  liquid  or  even  solid  matter  to  work 
through  them  and  collect  in  the  space  between  double  floors,  or  under 
the  stable,  creating  in  time  a  foul,  fermenting  mass  of  organic  matter 
which  keeps  the  stable  damp  and  filled  with  noxious  gases.  In  the 
disinfection  of  stables  for  pleuro-pneumonia  and  foot-and-mouth 
disease,  the  writer  saw  examples  of  tilth  between  and  under  floors, 
even  on  good  daily  farms,  which  has  made  him  partial  to  concrete. 
And  yet  it  is  possible  to  put  a  good  wooden  floor  in  a  cow  stable  and 
to  keep  the  stable  in  a  good  sanitary  condition. 

The  stables  should  have  solid  partitions  separating  completely  the 
mangers  and  the  greater  part  of  the  stalls.  Tuberculosis  is  very  apt 
to  spread  from  animal  to  animal  in  the  order  in  which  they  stand  in 
the  stable.  The  infection  occurs  through  the  small  particles  of  mucus 
or  of  tuberculous  material  which  are  forcibly  expelled  into  the  air  when 
an  atfected  animal  coughs,  or  through  the  saliva  which  soils  the  man- 
gers or  drinking  vessels,  or  through  the  animals  touching  noses  or 
licking  each  other.  A  solid  partition  as  high  as  the  animals'1  backs 
guards  against  such  infection  and  does  much  to  limit  the  spread  of  the 
contagion. 

The  method  of  watering  also  has  considerable  influence  on  the  spread 
of  tuberculosis.  It  is  quite  common  to  have  a  long  trough  in  front  of 
a  row  of  stalls  which  extends  the  length  of  the  row  and  is  filled  with 
water  from  one  end.  As  the  water  runs  into  this  trough  it  passes  in 
front  of  every  cow  in  the  row  and  carries  with  it  saliva  or  tuberculous 

79 


80  TUBERCULOSIS    OF    TIIK    KIM  ID-PRODUCING    ANIMALS. 

material  which  may  have  been  deposited  anywhere  along  its  course. 
The  last  cow  in  the  row  receives  water  that  may  have  been  contami- 
nated by  any  other  cow  in  the  row;  and  every  cow  in  the  row  except 
the  first  one  receives  the  washings  from  some  other  cow's  manger. 
So  long  as  the  cows  are  all  in  good  health  this  makes  little  difference, 
but  if  a  tuberculous  cow  with  virulent  saliva  is  stabled  in  such  a  row 
the  infection  of  the  other  animals  in  the  stable  is  greatly  facilitated. 
An  individual  drinking  basin  so  arranged  that  the  water  is  automat- 
ically kept  at  a  certain  level,  or  a  common  trough  in  the  open  air  and 
sunshine  which  has  running  water  and  from  which  the  surplus  water 
is  removed  at  the  surface,  is  to  be  preferred. 

Any  kind  of  material  may  be  used  for  the  walls  of  the  stable,  but 
the  inner  surface  should  be  as  free  from  projections  and  as  smooth  as 
possible.  The  object  should  be  to  secure  a  wall  that  is  easily  cleaned 
and  that  has  few  cracks  and  projections  to  hold  dust  and  dirt. 

The  amount  of  air  space  required  per  cow  depends  upon  the  effect- 
iveness of  the  system  of  ventilation.  In  a  stable  with  a  commodious 
passageway  in  front  and  back  of  the  cows,  and  with  a  free  space  over 
the  partitions  of  the  stables  reaching  9  or  10  feet  above  the  floor,  there 
will  be  space  enough  if  the  air  is  renewed  as  it  should  be.  There  are 
different  methods  of  ventilation  available  by  which  this  may  be  accom- 
plished without  producing  injurious  drafts  upon  the  animals,  and 
the  one  should  be  selected  which  appears  most  suitable  to  the  kind  of 
structure  that  is  to  be  erected. 

A  matter  of  some  importance  is  to  keep  the  cattle  in  the  open  air  as 
much  as  possible.  Not  only  does  this  improve  the  vigor  of  the  animals 
and  enable  them  better  to  resist  infection,  but  there  are  fewer  chances 
of  infection  at  pasture  or  in  open  pens  than  there  are  in  stables.  The 
plan  of  keeping  the  cows  in  stables  only  at  milking  time  in  winter  and 
of  turning  them  into  an  open  shed  during  the  remainder  of  the  time 
is  to  be  recommended,  except  in  very  severe  weather. 

There  should  also  be  special  attention  given  to  food  which  is  liable 
to  be  contaminated  with  tuberculous  infection.  The  young  calves 
should  be  given  the  milk  of  cows  known  to  be  healthy,  or,  in  case  this 
can  not  be  done,  the  milk  should  be  sterilized.  Sterilization  should 
also  be  practiced  with  skim  milk  fed  to  both  calves  and  pigs.  Hay 
contaminated  with  the  dust  from  stables  inhabited  by  tuberculous  cattle 
is  dangerous  for  healthy  animals. 

The  most  essential  precaution  to  be  observed  to  prevent  the  intro- 
duction of  tuberculosis  is  to  take  proper  measures  to  see  that  any  cattle 
brought  upon  the  premises  are  free  from  the  disease.  Such  animals 
should  be  tested  with  tuberculin,  but  this  alone  may  not  be  sufficient. 
Cattle  which  have  been  previously  tested  often  fail  to  react  to  the 
tuberculin  test  even  when  they  are  affected  with  tuberculosis,  conse- 
quently the  herd  from  which  the  animals  are  to  be  purchased  should 


THE    REPRESSION    OF   TUBERCULOSIS.  81 

be  examined  as  a  whole,  and  if  any  members  of  it  show  signs  of  tuber- 
culosis it  is  not  safe  to  receive  animals  from  that  herd. 

It  should  be  remembered  that  tuberculosis  is  a  very  common  disease, 
especially  among  dairy  cattle,  and  that  it  is  a  difficult  matter  to  add  new 
animals  frequently  to  a  herd  and  at  the  same  time  avoid  the  introduc- 
tion of  this  disease.  A  herd  free  from  tuberculosis  should  therefore 
be  renewed  and  increased  by  its  own  offspring  so  far  as  possible.  To 
bring  in  animals  from  other  herds,  either  temporarily  or  permanently, 
is  to  accept  a  risk  that  may  prove  disastrous. 

ERADICATION    OF   TUBERCULOSIS   FROM   THE    FARM. 

If  there  is  any  reason  to  suspect  the  existence  of  tuberculosis  in  a 
herd,  an  effort  should  be  made  at  once  to  determine  definitely  whether 
it  is  present  and  which  animals  are  affected  by  it. 

The  general  condition  of  the  animal  should  furnish  some  indication. 
If  any  of  the  animals  are  not  doing  well,  are  losing  flesh,  and  fail  to 
jaeld  the  amount  of  milk  which  is  to  be  reasonably  expected,  a  careful 
examination  should  be  made  of  them  to  determine  whether  their  tem- 
perature is  normal,  whether  there  are  signs  of  enlargement  of  the 
external  lymphatic  glands,  and  whether  abnormal  sounds  can  be 
detected  in  the  lungs.  The  examination  of  the  carcasses  of  any  ani- 
mals which  may  have  died  or  are  slaughtered  is  a  valuable  indication 
as  to  the  existence  of  the  disease  in  the  herd. 

The  most  reliable  means  of  determining  this  question  is,  however, 
the  tuberculin  test.  While  this  may  occasionally  fail  to  reveal  tuber- 
culosis in  an  individual  animal,  it  may  be  relied  upon  with  certainty 
to  reveal  the  existence  of  the  disease  in  a  herd.  If  this  test  indicates 
that  some  of  the  animals  are  tuberculous,  measures  should  be  at  once 
adopted  to  eradicate  the  disease  from  the  herd,  or  at  least  to  prevent 
its  further  spread.  In  case  there  are  only  one  or  two  animals  affected, 
and  these  are  not  especially  valuable,  the  best  plan  is  to  slaughter  them 
at  once  and  thoroughly  disinfect  the  stable  in  which  they  have  been 
kept,  If  a  large  proportion  of  a  herd  is  affected,  and  the  animals  are 
not  especially  valuable,  the  best  and  cheapest  plan  would  be  to  separate 
the  reacting  animals  from  the  healthy  ones,  and  to  have  the  former 
slaughtered  under  inspection  as  soon  as  they  can  be  put  in  proper  con- 
dition. It  is  probable  that  the  flesh  of  most  of  these  animals  would 
be  found  fit  for  food,  and  the  loss,  therefore,  would  not  be  very  great. 
In  case  the  herd  has  been  long  affected  and  many  of  the  animals  are  in 
an  advanced  stage  of  the  disease,  they  are  unfit  for  milk  production, 
and  the  sooner  they  are  slaughtered  the  less  will  be  the  loss. 

If  the  herd  contains  animals  which  are  valuable  for  breeding  pur- 
poses, the  Bang  system  of  management  or  some  modification  of  it  may 
be  profitably  adopted. 

1881— No.  38—06 6 


82  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

THE  BANG  METHOD  OP  ERADICATING  TUBERCULOSIS. 

What  is  generally  known  as  the  u  Bang  method"  of  eradicating  tuber- 
culosis'* is  entirely  voluntary  on  the  part  of  the  owners  and  consists 
essentialty  in  testing  the  entire  herd  with  tuberculin  and  in  isolating 
as  completely  as  possible  the  animals  which  do  not  react  and  which 
show  no  physical  sighs  of  the  disease,  and  also  in  isolating  the  calves 
from  reacting  cows  and  feeding  them  upon  the  sterilized  milk  of  react- 
ing cows  or  upon  the  milk  of  cows  which  have  not  reacted. 

Jn  making  the  tuberculin  test  it  was  found  that  in  Denmark,  where 
approximately  50  per  cent  of  the  cows  were  tuberculous,  22  per  cent 
of  the  herds  tested  were  entirely  free  from  this  disease.  In  many  other 
herds  but  a  few  animals  reacted,  and  it  was  often  an  easy  matter  to 
put  such  animals  in  a  separate  place  until  they  could  be  sold.  In  those 
cases  in  which  almost  all  grown-up  animals  reacted,  while  most  of  the 
young  cattle  were  sound,  it  was  often  possible  to  place  the  latter  in  a 
particular  stable  for  young  cattle,  as  such  a  stable  may  easily  be  made 
if  it  is  not  at  hand.  The  greatest  difficulty  of  isolation  occurred  when 
there  were  both  a  great  many  diseased  and  a  great  many  sound  cattle. 
In  this  case  it  was  usually  necessary  to  divide  the  stable  by  a  solid 
partition.  But  not  infrequently  the  construction  of  the  stable  was 
such  that  it  was  necessary  to  have  doors  in  the  partition  to  allow  feed- 
ing or  the  removal  of  the  manure.  This  arrangement  did  not  prove 
to  be  a  good  one,  as  there  was  too  much  opportunity  for  contagion 
even  if  the  doors  were  kept  shut  during  the  time,  they  were  not  in  use. 
In  some  cases  good  results  were  obtained  even  with  such  unsatisfac- 
tory stabling.  When  the  sound  animals  were  placed  in  completely 
isolated  stables,  and  especially  when  these  were  in  different  buildings, 
the  result  was  usually  very  satisfactory.  The  best  manner  of  isolation 
was  found  to  be  to  place  the  animals  upon  another  farm  from  that 
occupied  by  those  which  reacted. 

It  is  not  the  intention  by  this  plan  to  exterminate  tuberculosis 
promptly,  but  to  reduce  it  gradually  and  without  great  expense  to 
the  owner  of  the  infected  herd. 

If  a  stock  of  heavy  milking  cattle  has  been  built  up  by  years  of 
selection,  or  if  the  herd  is  purebred,  the  blood  may  be  retained  and 
the  breeding  operations  continued  without  interruption.  It  is  in  such 
cases  that  the  method  has  the  greatest  value.  With  ordinary  cows  it 
would  probably  be  to  the  financial  advantage  of  the  owner  to  estab- 
lish a  clean  stable  for  the  nonreacting  cows  and  for  newly  purchased 
ones,  all  of  which  should  of  course  be  tested,  and  to  turn  off  the 
reacting  cows  as  soon  as  possible  and  without  attempting  to  raise 
calves  from  them. 

In  formulating  the  Bang  method  it  was  assumed  that  animals  react- 
ing to  tuberculin  but  showing  no  evident  clinical  signs  of  tuberculosis 
are  in  the  majority  of  cases  affected  but  to  a  limited  extent  and  that 


THE    REPRESSION    OF    TUBERCULOSIS.  83 

therefore  it  is  not  necessary  to  kill  them.  They  may  live  and  keep 
apparently  healthy  for  years,  their  milk  as  a  rule  does  not  contain 
tubercle  bacilli,  and  by  pasteurization  every  danger  of  contagion  can  be 
avoided.  Their  flesh,  also,  will  generally  be  safe  for  food,  and  if  killed 
under  inspection  the  dangerous  carcasses  may  be  condemned.  In  the 
immense  majority  of  cases  such  cows  will  produce  healthy  calves. 

Among  the  reacting  cattle  there  will  always  be  some  subjects  in 
which  the  disease  develops,  so  that  they  become  disseminators  of  con- 
tagion. The  reacting  animals  must,  therefore,  be  separated  from  the 
sound  ones  as  thoroughly  as  possible.  The  newborn  calves  must  be 
immediately  removed  from  the  stable  where  the  reacting  cows  are 
placed,  and  they  must  have  boiled  or  pasteurized  milk.  The  sound 
section  should  be  tested  with  tuberculin  at  least  once  ever}'  year,  in 
order  that  the  animals  which  have  contracted  tuberculosis  in  spite  of 
the  separation  may  be  removed. 

Writing  with  reference  to  two  of  the  farms  where  this  plan  had  been 
in  operation  several  years,  Professor  Bang  said  that  in  spite  of  the 
separation  every  year  several  animals  have  fallen  by  renewed  test  of 
the  sound  division,  some  years  very  few,  some  years  more.  It  can 
not  be  expected  that  every  trace  of  the  contagion  will  be  excluded 
from  the  sound  section  when  the  two  sections  are  near  each  other, 
since  there  are  too  man}7  opportunities  for  the  contagion  to  be  carried 
in  various  ways,  as  by  people,  dogs,  cats,  rats,  etc.,  and  perhaps  also 
through  food,  as  in  Danish  stables  the  common  hayloft  is  usually  above 
the  stable.  Where  it  has  been  possible  to  place  the  two  sections  in 
quite  different  buildings  or  on  separate  farms  the  results  are  usually 
much  better. 

A    MODIFICATION    OF   THE   BANG    METHOD. 

Ujhelyi, 65  of  Hungary,  at  the  last  International  Veterinary  Congress 
referred  to  a  modification  of  the  Bang  method  which  he  had  practiced 
with  success  in  his  country. 

The  basis  of  the  Bang  method  of  tuberculosis  suppression,  he  said,  consists  on 
the  one  hand  in  separation  of  those  animals  which  respond  to  the  tuberculin  test 
from  the  others  and  on  the  other  hand  in  artificial  feeding  of  the  calves  with  milk 
warmed  to  80°  to  85°  C.  In  Denmark  the  artificial  feeding  was  usual  before,  and 
the  great  number  of  dairy  associations  rendered  it  possible  to  return  the  skim  milk 
pasteurized.  The  dairy  associations  in  Hungary  are,  on  the  whole,  smaller,  and  the 
purchase  of  pasteurizing  machines  can  not  be  carried  out;  neither  is  it  usual  here  to 
feed  calves  artificially.  I  have,  therefore,  while  taking  the  Bang  process  as  a  basis  for 
suppress!  ve  measures,  adopted  Hungarian  conditions  for  its  introduction  upon  sev- 
eral larger  and  smaller  estates — that  is,  the  expensive  and  complicated  process  of 
artificial  feeding  was  abandoned  and  the  calves  given  to  be  fostered  by  cows  which 
did  not  respond  to  the  test.  When  new  drafts  of  cows  arrived,  the  foster  mothers, 
were  selected  from  these;  if  none  could  be  found  unresponsive  to  the  test,  the  calves 
were  fed  by  their  own  mothers,  though  these  might  be  responsive;  and  care  was 
taken  meanwhile  to  allow  the  calves  to  be  with  their  mothers  only  while  feeding 
and  to  remove  them  from  the  cow  house  immediately  after  weaning.  Of  these  calves 
fed  of  necessity,  though  under  proper  precautions,  by  mothers  responsive  to  the 
test,  hardly  more,  on  a  yearly  average,  than  10  per  cent  were  found  to  react,  while 
of  those  fed  by  nonreacting  foster  mothers  the  number  reacting,  on  a  yearly  average, 
was  2  to  6  per  cent — results  that,  even  under  the  application  of  the  original  Bang 
process,  could  hardly  have  been  bettered.  At  least,  of  the  10,533  young  animals 


84  TUBERCULOSIS    OF   THE    FOOD- PRODUCING    ANIMALS. 

artificially  reared  and  half-yearly  examined  upon  the  Archduke  Frederic's  estate  at 
Magyar-Ovdr,  400— i.  e.,  3.7  per  cent — were  found  to  react  to  the  test,  while,  on  tin- 
other  hand,  during  my  own  researches  of  7,296  young  animals  only  239,  or  3.3  per 
cent,  reacted.  It  is  to  be  noted  that  the  examinations  on  three  out  of  eight  estates 
took  place  every  nine  months. 

I  lately  had  occasion  to  introduce  and  without  much  difficulty  to  apply  the  Bang 
process  of  suppression,  especially  in  the  form  adapted  to  our  peculiar  conditions,  not 
only  to  small  establishments  of  some  70  head,  but  to  places  with  a  stock  of  150  to 
250  and  to  large  establishments  of  400  to  700.  But  the  process  has  also  been  applied 
here  in  its  original  form  at  Mezohegyes,  for  instance,  on  a  farm  of  over  1,000  head, 
which  was  completely  freed  from  the  disease  in  four  or  five  years;  also,  on  the  Mag- 
yar-Ovdr estate,  on  a  farm  of  over  5,000  head,  where  after  five  years'  treatment 
three-fifths  of  the  stock  are  free  from  tuberculosis. 

SUCCESSFUL   TREATMENT   OF    A    WISCONSIN    HERD. 

Russell,66  of  the  Wisconsin  Agricultural  Experiment  Station,  has 
given  an  interesting  account  of  the  successful  treatment  of  an  out- 
break of  tuberculosis  in  a  herd  of  cows  in  that  State.  The  measures 
were  carried  out  in  accordance  with  advice  received  from  the  experi- 
ment station. 

Eight  years  before  this  account  was  written  a  thrifty  farmer  in  one  of  the  eastern 
counties  of  the  State  decided  that  he  could  have  better  cows  than  those  which  he 
then  possessed.  He  did  not  sell  all  that  he  had  and  buy  new  ones  to  take  the  place 
of  the  old  herd,  but  he  purchased  a  few  p*urebred  animals  that  he  had  reason  to 
believe  were  better  milk  producers  than  his  own  cows.-  With  this  influx  of  new 
blood  he  started,  as  thousands  of  dairymen  have  done,  to  "build  up"  a  herd  by 
gradual  selection  of  the  best  animals. 

When  this  purebred  stock  was  first  bought  it  was  kept  apart  from  the  balance  of 
the  herd  until  three  years  later,  at  which  time  the  herd  was  redivided  on  a  basis  of 
age,  all  young  animals  being  kept  together  on  one  side  of  the  barn,  while  the  mature 
animals  were  stabled  on  the  other  side.  . 

The  following  year  some  of  the  purebred  cows  began  to  fail,  and  within  another 
year  2  of  them  died  of  what  later  was  determined  to  be  tuberculosis.  The  owner 
at  this  time  was  ignorant  of  the  true  nature  of  the  malady,  as  the  slow  wasting  away 
of  the  animals  had  not  especially  impressed  him.  When  the  character  of  the  disease 
was  ascertained  by  a  post-mortem  examination,  a  tuberculin  "test  of  the  entire  herd 
was  at  once  made,  under  the  auspices  of  the  experiment  station,  and  the  surprising 
fact  established  that,  with  three  exceptions  (13  out  of  16),  all  of  th'e  mature  animals 
in  the  herd  reacted.  In  addition  to  this,  3  head  of  young  stock  also  responded  to 
the  test. 

Supposing  that  some  of  the  original  cows  were  infected  with  the  disease  at  time  of 
purchase,  it  is  probable  that  the  malady  was  disseminated  among  the  mature  animals 
from  1894  to  1896.  In  this  brief  space  of  time  the  outbreak  had  spread  so  that 
nearly  every  mature  animal  in  the  herd  was  more  or  less  involved.  This  had 
happened  practically  unsuspected  by  the  owner. 

Believing  that  in  this  case  it  wras  possible  to  restore  the  herd  to  a  perfectly  healthy 
condition  and  that  it  could  be  done  with  less  expense  than  it  would  be  to  kill  all  the 
animals  that  reacted  and  fill  their  places  with  other  stock,  the  following  method  was 
proposed  to  the  owner  and  adopted  by  him: 

Separate  at  time  of  test  all  reacting  from  nonreacting  animals,  keeping  them  prac- 
tically as  two  independent  herds.  Breed  these  reacting  animals  under  careful  con- 
ditions, separating  the  calves  at  birth  from  their  mothers,  feeding  them  on  thoroughly 
pasteurized  milk  of  reacting  cows  (or  milk  from  nonreacting  animals).  All  healthy 
cows,  and  calves  from  both  affected  and  healthy  sections,  to  be  kept  in  quarters 
known  to  be  free  from  tuberculous  contagion.  The  disposition  of  the  product  of  the 
reacting  herd  may  be  varied  to  suit  the  exigencies  of  the  occasion,  but  in  any  case  it 
should  be  treated  by  pasteurizing  so  as  to  render  it  innocuous. 

The  conditions  were  such  as  might  be  found  on  hundreds  of  farms.  No  other 
building  was  available  in  which  either  the  healthy  or  the  affected  part  of  the  herd 
could  be  kept,  and  it  was  therefore  necessary  to  arrange  quarters  in  the  original 
stable  so  as  to  prevent  contact  of  one  section  of  the  herd  with  another.  This  was 
done  by  throwing  a  partition  made  of  a  single  thickness  of  boards  across  the  stable. 
The  two  sections  of  the  herd  were  pastured  in  separate  paddocks  and  watered  in  dif- 


THE    REPRESSION    OF    TUBERCULOSIS. 


85 


ferent  tanks.  It  was  somewhat  hazardous  to  allow  direct  passage  between  the  two 
compartments,  and  also  to  bring  the  food  for  the  healthy  section  through  the  room 
occupied  by  the  diseased  stock,  but  such  an  arrangement  under  the  circumstances 
was  the  only  practical  one  that  could  be  instituted. 

Before  the  rebuilding  of  the  herd  was  begun  it  was  necessary  to  disinfect  the  whole 
stable  thoroughly.  All  litter  and  loose  material  were  first  cleaned  out,  so  as  to  give 
better  penetration  to  the  disinfectant;  then  the  stalls  and  mangers  were  thoroughly 
washed  with  a  hot  solution  of  lye,  the  walls  and  ceilings  being  treated  with  a  coat  of 
milk  of  lime  (a  thin  whitewash  made  from  freshly  slaked  lime). 

The  first  test  was  made  January  2,  1896.  On  January  10  the  herd  was  divided  into 
two  sections,  and  from  that  time  these  divisions  were  handled  as  two  separate  herds. 
Various  animals  were  disposed  of  from  time  to  time,  and  a  final  test  of  the  entire  herd 
was  made  in  February,  1899.  The  following  table  shows  the  results  of  the  different 
tests  made  of  the  two  sections  of  this  herd : 

Actual  condition  of  the  herd  at  times  of  different  tests. 


Date  of  test. 

Tuberculosis  sec- 
tion and  its  prog- 
eny. 

Healthy  section 
and  its  progeny. 

Healthy. 

Diseased. 

Healthy. 

Diseased. 

January,  18%  .  .                  

0 
4 

11 

13 
27 

16 
14 
13 
10 

7 

18 
17 
19 
23 
37 

0 
0 
0 
0 
0 

May,  18%  

April  1897 

December,  1897. 

February,  1899  .... 

In  no  case  did  any  of  the  animals,  originally  pronounced  tuberculous,  ever  fail  to 
react  in  any  of  the  subsequent  tests.  It  is  also  remarkable  that  no  case  of  disease 
appeared  in  the  healthy  section  of  the  herd.  One  of  the  striking  facts  noted  in  these 
investigations  was  the  way  in  which  the  disease  progressed  in  the  individual  animals. 
By  1896,  two  of  the  original  cows  had  died.  Of  the  16  affected  when  the  first  test  was 
made,  several  were  killed  for  demonstration  purposes.  In  1896  and  1897,  four  had  to 
be  destroyed  on  account  of  the  progress  of  the  disease;  in  1898,  two  more  broke  down, 
and  up  to  August,  1899,  one  more  succumbed. 

It  was  noteworthy  in  those  cases  in  which  the  disease  gained  the  ascendency  over 
the  animal  that  the  decline  was  generally  rapid  toward  the  last.  The  animal  main- 
tained itself  in  good  condition  until  some  set  of  causes  threw  it  from  a  chronic  latent 
tuberculosis  into  an  acute  stage.  The  intense  cold  of  the  last  winter  hastened  this 
change  in  one  case;  in  two  other  instances  the  inciting  cause  was  evidently  the  strain 
of  calving.  A  fact  of  great  practical  value  was  that  the  diseased  condition  generally 
remained  comparatively  quiescent  for  a  number  of  years,  the  resisting  powers  of  the 
body  being  able  to  hold  the  disease  germ  in  check;  then  a  sudden  turn  for  the  worse 
occurred,  generally  as  a  result  of  some  external  inciting  cause. 

ERADICATION    FROM    A    CONNECTICUT    HERD. 

The  eradication  of  tuberculosis  from  the  herd  of  the  Connecticut 
Agricultural  College26  is  also  an  object  lesson  as  to  what  may  be 
accomplished  by  intelligent  management  of  a  tuberculous  herd. 

The  healthy  and  reacting  animals  were  separated  and  placed  in  adjacent  barns; 
they  also  had  separate  yards  and  watering  places,  and  at  no  point  did  they  come  in 
contact,  except  that  the  same  service  bulls  were  used  for  both  herds.  The  barn  in 
which  the  reacting  herd  was  quartered  was  well  ventilated  and  admitted  consider- 
able sunlight.  As  little  passing  as  possible  was  permitted.  The  attendants  who 
milked,  fed,  and  cared  for  the  herds  were  instructed  to  wait  upon  the  healthy  herd 
first  and  later  upon  the  affected  herd,  and  only  in  this  order.  The  milk  from  the 
reacting  herd  was  pasteurized  and  used  for  butter  making.  The  calves  from  this 
herd  were  removed  when  dropped  and  quartered  with  the  healthy  herd. 

In  this  case  it  was  not  practicable  to  remove  the  nonreacting  animals  to  new  quar- 
ters and  leave  the  reacting  animals  in  the  old  quarters,  and  therefore  the  old  barn 
was  thoroughly  cleaned  and  disinfected  with  a  5  per  cent  solution  of  crude  carbolic 


86 


TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 


acid.     The  following  table  shows  the  gradual  elimination  of  tuberculosis  from  the 
herd: 


Number 

of  ani- 

Number 

Date  of  tuberculin  test. 

mals  test- 

of reac- 

ed in  the 

tions. 

herd. 

December  28,  1898  

49 

12 

Mav22,  1899  

35 

3 

December  7,  1899  

36 

2 

April  16,  1900  

36 

1 

November  24  1900                  ...                  ... 

48 

0 

March  20,  1901  

47 

0 

February  17,  1902  

35 

0 

It  is  not  known  whether  the  reactions  which  occurred  after  the 
first  test  were  due  to  too  lax  a  quarantine,  to  an  inefficient  disinfection 
of  the  old  barn,  or  whether  they  were  incipient  cases  that  developed 
later.  The  advisability  of  testing  once  or  twice  a  year  is  apparent. 

The  successful  and  rapid  eradication  of  the  disease  in  the  herd  of 
the  Connecticut  Agricultural  College  shows  that  the  arrangements 
were  well  made  and  the  quarantine  rigidly  enforced.  The  results  of 
this  method  are  not  always  so  favorable,  however,  as  is  shown  by  the 
following  instance  related  by  Regner21  as  having  been  observed  in  the 
tuberculosis  work  in  Sweden. 

RECOMMENDATIONS   OF   REGNER,  OF  SWEDEN. 

In  one  locality  the  struggle  against  tuberculosis  had  been  kept  up 
for  seven  years  in  three  herds  with  the  result  as  shown  in  the  table 
which  follows: 


Year. 

Number 
of 
animals. 

Number 
reacting. 

Year. 

Number 
of 
animals. 

Number 
reacting. 

1897 

331 

258 

1901  

312 

22 

1898  

197 

39 

1902  

391 

15 

1899 

226 

7 

1903 

408 

2 

1900          .   . 

286 

14 

1904    

416 

83 

Of  the  animals  reacting  in  1904,  80  were  in  a  stable  where  there 
were  only  123  head  of  cattle.  Upon  investigating  the  cause  of  this 
remarkable  increase  in  the  number  of  diseased  animals  it  was  found 
that  a  cow  which  had  reacted  in  1897,  but  after  that  year  had  not 
reacted,  and  which  had  been  left  with  the  sound  stock,  had  developed 
open  tuberculosis  (lung  and  laryngeal  tuberculosis)  during  the  last 
year  and  had  stood  a  part  of  the  time  at  each  of  the  four  feeding  places. 

Regner  is  of  the  opinion  that  a  herd  of  cattle  seriously  affected  with 
tuberculosis  should  not  be  tested  with  tuberculin,  but  that  such  animals 
as  show  signs  of  the  disease  by  other  tests  should  be  removed,  and  that 
sound  stock  should  be  bred  from  the  apparently  sound  stock  in  the 
tuberculous  herd.  He  gives  the  following  rules,  supplementary  to 
perfect  isolation,  infection-destroying  treatment  of  milk  food,  and 
disinfection  of  cow  houses,  as  deserving  special  emphasis : 


THE    REPRESSION    OF    TUBERCULOSIS.  87 

1.  That  the  old  stock  should  from  time  to  time  be  freed,  by  the  use  of  clinical  and 
bacterioscopic  methods,  from  individual  animals  in  which  tuberculosis  has  shown 
itself. 

2.  That  the  newborn  calves  of  this  stock  should  be  immediately  brought  to  the 
protected  stock. 

3.  That  the  raw  milk  should  be  taken  from  the  mother  with  such  precautions  that 
exterior  infection  of  it  should  as  far  as  possible  be  rendered  impossible. 

4.  That  the  calf  should  be  tested  as  soon  as  possible  with  tuberculin — the  first  time 
when  8  days  old,  the  second  time  when  half  a  year  old,  and  afterwards  once  a  year. 

5.  That  every  animal  so  tested  and  found  to  react  should  be  marked  to  prevent 
mistakes  in  isolating,  and  that  a  clinical  examination  should  be  held  upon  any  ani- 
mal whose  appearance  and  behavior  (especially  in  the  case  of  repeated  coughing) 
should  give  cause  for  it. 

6.  That  the  animals  should  be  exactly  numbered  (first  by  earmarks,  later  by  brand- 
ing the  number  on  one  horn)  and  entered  in  books. 

7.  That  animals  from  other  stocks,  no  matter  how  young,  should  only  be  admitted 
into  the  protected  establishment  from  stocks  free  from  reaction,  or,  in  case  that  this 
presents  insurmountable  difficulties,  from  other  stocks  only  with  certain  precautions. 

According  to  Regner's  observations  a  single  incautious  purchase  for 
a  herd  free  from  reaction  may  in  a  short  time  bring  to  naught  the 
the  result  of  a  year's  or  of  many  years'  work  devoted  to  rooting  out 
tuberculosis  in  that  herd.  The  condition  generally  made  that  the  pur- 
chased animal  should  be  free  from  reaction  is  not  sufficient  in  itself. 
Should  the  purchased  animal  come  direct  from  a  stock  well  known  to 
be  free  from  reaction,  and  which  has  been  for"  years  subject  to  pro- 
tective precautions,  and  should  the  animal  have  been  born  and  reared 
in  that  stock,  then  all  is  well.  In  any  other  case  the  purchaser  must 
demand  such  information  as  to  the  stock  from  which  the  purchase  is 
to  be  made  as  may  clearl}7  show  the  prevalence  of  tuberculosis.  The 
stock  must  therefore  be  tested  and  the  result  laid  before  the  pur- 
chaser. Should  the  farmer  decide  to  purchase  from  an  infected  herd 
animals  free  from  reaction,  and  which  have  also  been  tested  clinically 
with  negative  results,  he  would  do  well  to  disinfect  the  animal  after 
its  arrival  at  his  farm,  above  all  with  regard  to  the  hoofs  and  the  lower 
part  of  the  legs,  and  if  possible  keep  it  half  a  year  in  quarantine. 
Should  local  conditions  not  admit  of  this,  the  animal  should  be  placed 
in  a  stall  apart  from  the  others  and  must  not  be  removed  from  its 
place  until  it  has  undergone  a  new  testing  with  a  double  quantity 
of  tuberculin,  which  in  any  case  must  be  made  after  the  interval 
mentioned. 

IMMUNIZATION  IN  CONNECTION  WITH  THE  BANG  METHOD. 

It  appears  probable  from  the  results  which  have  been  published  of 
recent  researches,  the  more  important  of  which  have  been  summarized 
above,  that  the  immunization  of  bovine  animals  will  be  of  great  assist- 
ance in  freeing  a  herd  from  disease  when  practiced  in  connection  with 
the  Bang  method.  In  this  case  the  young  cattle  which  do  not  react  to 
the  tuberculin  test,  and  all  of  the  calves  when  a  week  old,  would  be  given 
an  immunizing  injection  and  removed  to  a  stable  free  from  infection. 
If  the  method  selected  requires  that  two  doses  should  be  given,  the 
second  dose  should  be  administered  to  the  animals  in  the  uninfected 
stable  after  a  proper  interval  of  time  has  elapsed.  As  several  months 


SS  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

arc  required  for  the  development  of  the  immunity  after  the  vaccine  is 
injected,  it  is  essential  that  there  should  be  complete  isolation  from 
infected  cattle  during  this  period,  as  required  by  the  Bang  method. 

It  appears  that  calves  may  be  very  successfully  immunized,  but  it 
is  not  certain  that  this  is  true  of  grown  cattle,  and  therefore  the 
tuberculin  test  and  isolation  must  be  relied  upon  with  the  adult  ani- 
mals. The  duration  of  the  immunity  is  yet  uncertain,  and  for  this 
reason  it  is  difficult  to  estimate  the  degree  of  assistance  which  will  be 
rendered  by  immunization. 

The  immunization  of  cows,  assuming  that  investigations  show  that 
this  may  be  successf  u\\y  accomplished,  would  raise  the  question  as  to 
the  danger  which  this  method  might  cause  to  the  consumer  of  the 
milk.  The  immunizing  material  is  the  human  tubercle  bacillus  which 
has  not  been  deprived  of  all  its  dangerous  qualities,  and  when  this  is 
injected  into  the  blood  it  causes  an  elevation  of  temperature  and  per- 
haps other  signs  of  illness.  Is  there  danger  of  this  bacillus  contami- 
nating the  milk  during  the  period  that  it  is  circulating  in  the  blood  of 
the  animal?  And,  further,  does  the  illness  caused  b}^  the  immunizing 
dose  of -the  vaccine  have  any  injurious  effect  upon  the  composition  of 
the  milk  which  might  render  this  liquid  injurious  to  the  consumer? 
These  are  questions  of  a  serious  nature,  and  they  should  receive  a 
scientific  answer  before  the  immunization  of  milk-producing  cows  is 
practiced. 

Assuming,  for  the  moment,  that  the  immunization  of  milch  cows  is 
practicable  and  proper,  it  would  follow  that  all  nonreacting  animals 
should  receive  an  immunizing  injection  when  they  are  placed  in  the 
isolated  stable.  This  should  guard  against  the  continued  appearance  of 
the  disease  in  the  healthy  section  of  the  herd,  as  has  been  so  frequently 
the  case  where  perfect  isolation  could  not  be  maintained. 

It  is  not  probable,  however,  that  isolation  of  the  healthy  animals 
can  be  altogether  dispensed  with.  The  long  period  which  is  required 
for  the  development  of  the  immunity  would  make  the  chance  of  infec- 
tion far  too-great  if  the  nonreacting  vaccinated  animals  remained  in 
the  same  stable  with  those  which  were  diseased.  If,  however,  the 
vaccination  were  conducted  during  the  season  of  pasturage,  and  the 
animals  stabled  only  during  milking,  and  particularly  if  but  a  small 
proportion  of  the  herd  reacted,  it  seems  probable  that  the  isolation 
might  be  omitted  without  serious  consequences. 

Experience  writh  immunization  is,  as  yet,  so  limited,  and  so  many  of 
the  accounts  published  appear  to  be  biased  by  commercial  considera- 
tions, that  it  is  too  soon  to  predict  definitely  the  extent  of  its  useful- 
ness as  a  practical  measure  for  the  control  of  tuberculosis.  If  it  aids 
in  any  degree  in  eradicating  this  disease,  or  in  lessening  the  burden 
which  falls  upon  the  owners  of  diseased  herds,  it  will  be  a  most  welcome 
addition  to  our  resources. 


THE    REPRESSION    OF    TUBERCULOSIS.  89 

DESTRUCTION  OF  REACTING  ANIMALS  AND  CREATION  OF  A  SOUND  HERD. 

The  objection  to  the  Bang  system  and  to  all  modifications  of  it  is  the 
length  of  time  that  tuberculous  animals  must  be  kept  on  the  premises, 
injuring  the  reputation  of  the  herd  and  causing  much  extra  work  in 
caring  for  two  herds,  sterilizing  milk,  and  taking  precautions  to  pre- 
vent infection  of  the  healthy  animals.  It  is  true  that  the  prescribed 
precautions  are  not  always  carried  out,  and  equally  true  that  in  such 
cases  there  is  usually  not  very  marked  success  in  getting  rid  of  the 
disease.  For  this  reason  it  has  been  considered  best,  where  the  cattle 
have  no  special  value  for  breeding  purposes,  to  slaughter  reacting  ani- 
mals, and  disinfect  the  stable  and  thus  immediately  to  stamp  out  the 
disease.  Most  dairj^men  prefer  this  plan  as  the  more  economical  of 
the  two. 

The  eradication  of  tuberculosis  from  the  herd  of  the  Maine  Agri- 
cultural College67  is  a  valuable  example  of  what  may  be  done  by  this 
plan. 

Since  some  years  before  1886  until  within  two  years,  whenever  the  college  has  kept 
any  cattle  on  the  college  farm  some  of  them  have  been  affected  with  tuberculosis. 
Before  1886  cattle  occasionally  died  from  this  disease  or,  in  absence  of  exact  knowl- 
edge of  their  condition,  were  sold  for  beef  or  otherwise  disposed  of  on  account  of  age 
or  unthriftiness.  Well-bred  young  animals  were  sold  to  improve  other  herds  and 
sometimes  carried  tuberculosis  with  them. 

In  1886  the  cattle  were  so  badly  diseased  that  it  was  considered  best  to  kill  the 
entire  herd.  After  the  herd  was  destroyed  the  barns  were  disinfected  with  some 
care  and  no  new  stock  was  introduced  for  about  a  year.  In  1889  considerable  new 
stock  was  purchased  from  different  sources,  and  in  less  than  a  year  from  the  time 
they  were  purchased  two  of  the  animals  were  found  to  be  diseased  and  were  killed. 
Again  the  barn  was  disinfected,  but  new  cases  of  disease  were  frequently  being  dis- 
covered in  the  herd. 

In  1892  tuberculin  became  available  for  the  detection  of  tuberculosis,  and  experi- 
ments were  soon  made  at  the  college  to  test  its  value. 

By  1893,  having  become  convinced  of  the  value  of  tuberculin,  every  bovine  animal 
on  the  farm  down  to  the  youngest  calf  was  tested,  and  those  that  reacted  to  the  test 
were  killed.  This  made  a  large  hole  in  the  herd  and  required  the  sacrifice  of  some 
of  the  most  valued  animals,  but  it  is  believed  the  results  have  fully  justified  the 
course  taken. 

In  order  to  meet  the  demands  for  dairy  products  it  was  considered  necessary  to 
replace  the  cows  killed,  and  ordinary  grade  and  native  cows  that  answered  the 
requirements  were  purchased  from  near-by  sources.  Every  precaution  was  taken  to 
procure  sound  animals,  and  before  they  were  introduced  into  the  barns  they  success- 
fully passed  the  tuberculin  test,  but  as  it  was  late  in  the  fall  and  the  barn  was  full  of 
hay  and  grain  it  was  not  considered  practicable  to  disinfect  the  barn.  The  lintel  was 
disinfected,  but  not  the  rest  of  the  barn  until  the  following  summer. 

During  the  winter  of  1893-94  and  the  following  spring  several  cases  of  tuberculosis 
developed,  some  of  them  being  cows  purchased  the  fall  before  from  healthy  herds, 
and,  according  to  every  known  test,  healthy  animals  themselves.  They  must  have 
contracted  the  disease  in  the  college  barns.  In  the  summer  of  1894  the  barn  was 
disinfected,  and  since  that  time  comparatively  few  cases  of  tuberculosis  have  been 
found,  the  last  case  being  discovered  in  the  fall  of  1897.  In  1896,  the  barn  was  again 
disinfected  in  a  very  thorough  manner.  Since  then  but  two  cases  have  been  found, 
and  both  of  them  were  discovered  before  it  was  possible  that  they  should  have 
infected  their  surroundings  or  other  cattle.  Since  October,  1897,  no  new  case  has 
been  discovered,  although  the  entire  herd  was  tested  in  1897  and  again  in  1898.  It 
is  believed  that  since  October,  1897,  the  herd  has  been  entirely  free  from  tuberculosis 
for  perhaps  the  first  time  in  its  history.  The  herd  now  numbers  51  head  of  all  ages, 
most  of  these  bred  on  the  farm. 

The  method  of  disinfection  by  which  the  barn  was  freed  from  the  contagion  is  of 
much  interest: 

All  the  hay,  grain,  and  farming  tools  were  removed  from  the  barns,  the  only 
exception  being  the  hoes,  shovels,  and  forks  that  had  to  be  used  there.  Every  mov- 


90  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

able  thing  that  had  been  in  the  barn  with  the  diseased  cattle,  or  after  the  diseased 
cattle  were  removed,  before  the  barn  was  disinfected,  was  taken  out,  or,  if  left  in  the 
barn,  was  disinfected  in  the  same  manner  as  the  barn  itself.  Then  with  brooms  all 
dust  and  dirt  that  could  be  moved  was  swept  into  the  basement  or  out  of  doors  into 
the  sunlight.  Then  with  a  hand  pump  mounted  on  a  barrel,  such  a  pump  as  is  com- 
monly used  in  spraying  orchards  or  potato  fields,  the  disinfecting  solution  was  thrown 
with  considerable  force  against  every  inch  of  the  woodwork  of  the  barn,  into  every  crack 
and  crevice  where  dust,  laden  with  disease  germs,  might  lodge.  The  workmen  com- 
menced in  the  roof  and  worked  downward,  making  thorough  work  of  it  as  they  went 
along.  By  using  the  pump  this  was  not  a  very  expensive  operation.  Including  the 
cost  of  the  material  and  labor,  the  expense  of  cleaning  and  disinfecting  a  barn  50 
by  100  feet  with  18- foot  posts  and  basement  was  about  $25.  This  did  not  include  the 
cost  of  the  pump,  which  was  but  little  injured,  and  had  before  and  has  since  that 
time  been  used  for  other  purposes.  The  disinfecting  solution  was  made  by  dissolv- 
ing 1  part,  by  weight,  of  corrosive  sublimate  in  about  1,000  parts  of  water.  The 
pump  was  mounted  on  a  50-gallon  barrel  and  a  little  more  than  £  pound  of  the  sub- 
limate was  used  for  a  barrel  of  water.  The  pulverized  corrosive  sublimate  was  pur- 
chased and  this  was  dissolved  in  hot  water,  as  it  dissolves  very  slowly  in  cold  water. 
The  sublimate  and  its  solution  should  be  kept  in  glass  or  wooden  vessels;  it  corrodes 
metal.  The  solution  is  poisonous  if  taken  in  sufficient  quantities,  so  it  should  never 
be  left  uncovered  where  animals  can  get  at  it. 

Another  means  that  has  been  used  in  keeping  this  herd  free  from  tuberculosis  has 
been  the  testing  with  tuberculin  of  all  animals  purchased.  By  this  means  the  pur- 
chase of  diseased  animals  that  were  satisfactory  in  other  respects  has  been  avoided. 
When  convenient  the  animals  purchased  were  tested  before  they  were  brought  to 
the  farm.  In  other  cases  they  were  tested  on  the  college  farm  before  they  were 
admitted  to  the  barns  with  the  other  cattle.  In  two  cases  the  introduction  of  tuber- 
culous cattle  into  the  herd  was  avoided  by  this  very  simple  precaution. 

A  thorough  disinfection  is  necessary,  and  this  should  be  practiced 
immediately  after  the  diseased  animals  are  removed  from  the  stable. 
Russell  and  Hastings34  say  that  it  is  manifestly  useless  to  eradicate 
this  disease  from  a  herd  unless  at  the  same  time  the  infected  quarters 
are  subject  to  a  thorough  disinfection.  One  case  that  came  to  their 
attention  sufficiently  illustrates  this  point.  Within  the  past  two  years 
a  herd  of  cows  was  tested  and  the  larger  part  of  the  herd  condemned 
by  the  test  and  slaughtered.  A  post-mortem  examination  showed 
many  of  them  to  be  badly  diseased.  A  short  time  afterwards  a  new 
herd  was  purchased  and  introduced  into  the  same  quarters.  In  less 
than  a  year  it  was  found  that  many  of  this  second  herd  had  also  acquired 
this  same  disease.  Undoubtedly  they  contracted  the  same  from  the 
infected  quarters  in  which  they  were  placed. 

In  order  to  carry  out  such  a  disinfection  there  should  be  first  a 
thorough  cleaning  with  brooms  to  remove  all  litter  and  dust,  not  only 
from  the  floor,  but  from  the  walls,  the  roof,  and  all  projections  where 
dust  may  lodge.  All  loose  boards  and  decayed  woodwork  should  be 
removed.  The  floor  of  the  stable  should  be  washed  with  water  and 
the  mangers  and  stalls  with  a  hot  solution  of  lye.  The  whole  interior 
of  the  stable  should  then  be  sprayed  with  the  disinfecting  solution. 
Every  crack  and  crevice  should  be  filled  with  disinfectant  and  every 
part  of  the  walls  should  be  covered.  There  are  many  different  kinds 
of  spray  pumps  which  are  available  for  this  purpose. 

Poisonous  disinfectants  or  those  having  a  strong  and  lasting  odor 
should,  if  possible,  be  avoided.  A  thin  lime  wash  made  from  freshly 
burned  lime  is  the  most  satisfactory  disinfectant  to  use  about  a  stable. 


THE    REPRESSION    OF   TUBERCULOSIS.  91 

Its  activity  may  be  increased  by  the  addition  of  4  ounces  of  formalin 
to  1  gallon  of  lime  wash.  Corrosive  sublimate  and  carbolic  acid  are 
often  recommended  for  this  purpose,  but  as  both  are  dangerous  poi- 
sons, and  as  the  latter  has  an  objectionable  and  persistent  odor,  it  is 
deemed  best  to  use  lime  wash  and  formalin,  which  probabty  are  just  as 
effective  in  destroying  the  tubercle  bacillus. 

In  adding  new  animals  to  the  herd  they  should  be  tested  with  tuber- 
culin before  purchasing,  and  then,  if  possible,  they  should  be  kept  in  a 
separate  stable  for  six  months  and  afterwards  tested  a  second  time 
before  they  are  placed  with  the  healthy  cattle.  This  precaution  will 
usually  be  sufficient  to  prevent  the  reinfection  of  the  herd  by  the  pur- 
chased animals.  It  should  be  remembered,  however,  that  some  of  the 
animals  of  the  herd  which  did  not  react  may  nevertheless  have  been 
infected,  and  to  detect  any  cases  of  this  kind  there  should  be  a  second 
test  made  of  the  entire  herd  in  about  six  months.  If  any  reactions 
occur,  the  reacting  animals  should  be  removed  and  the  stable  disin- 
fected as  before.  The  herd  should  be  tested  at  least  once  a  year  for 
two  or  three  years  after  the  last  reaction  has  occurred. 

With  hogs  the  eradication  of  tuberculosis  from  a  badly  infected 
herd  is  a  difficult  matter.  The  best  course  to  pursue  is  probably  to 
destroy  the  entire  herd,  thoroughly  disinfect  the  pens,  and  after  a  few 
months  to  start  with  a  new  herd  known  to  be  free  from  disease.  A 
boar  may  be  retained  from  the  old  herd,  if  considered  very  desirable, 
but  it  should  be  kept  isolated  from  the  new  herd  except  during  service. 
For  the  same  reason  it  is  well  to  keep  newly  purchased  boars  similarly 
isolated.  This  simple  precaution  may  often  prevent  the  infection  of 
a  herd.  The  increasing  prevalence  of  tuberculosis  in  swine  empha- 
sizes the  importance  of  precautionary  measures  being  adopted  by  the 
breeders  of  these  animals. 

STATE  AID  FOR  THE  ERADICATION  OF  TUBERCULOSIS. 

In  the  eradication  of  a  disease  so  widely  disseminated,  and  one  which 
causes  such  serious  losses  to  the  animal  industry  of  the  country,  there 
should  be  assistance  offered  by  the  State  in  order  to  relieve  the  bur- 
dens which  fall  upon  the  owners  of  live  stock.  A  considerable  num- 
ber of  States  have  shown  a  disposition  to  come  to  the  assistance  of 
farmers  whose  stock  is  affected,"but  the  assistance  has  sometimes  been 
coupled  with  conditions  which  made  it  unwelcome.  In  some  States 
compulsory  testing  and  the  slaughter  of  reacting  animals  have  been 
required,  but  this  has  not  been  a  popular  measure.  It  is  essential  that 
a  plan  should  be  devised  which  will  meet  with  the  approval  of  the 
stock  owners  and  which  will  aid  them  without  being  too  burdensome 
in  its  conditions.  There  are  certain  measures  which  have  been  adopted 
by  individual  States  which  have  accomplished  satisfactory  results,  but 
which  would  be  far  more  successful  if  adjoining  States  would  adopt 
the  same  or  similar  regulations.  Among  the  reasonable  measures 


92  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

which  a  State  may  adopt  for  the  repression  of  tuberculosis  the  follow- 
ing may  be  mentioned: 

1.  Cattle  which  are  brought  into  a  State  for  breeding  or  dairy  pur- 
poses may  be  tested  with  tuberculin,  and  those  which  react  may  be 
refused  admission  to  the  State.     In  connection  with  this  measure  it 
should  be  provided  that  cattle  which  have  been  tested  by  the  authori- 
ties of  another  State  or  of  the  Federal  Government  and  found  free 
from  disease  should  be  allowed  admission  without  being  retested. 
The  testing  of  animals  coming  into  a  State  is  essential  in  any  effort  to 
control  this  disease,  and  is  one  of  the  first  measures  which  should  be 
enforced  in  any  effort  to  eradicate  it. 

2.  There  should  be  an  inspection  of  all  slaughtered  animals  coming 
from  breeding  or  daily  herds  within  the  State  in  order  to  discover  in 
what  herds  the  disease  exists.     Animals  from  the  greater  part  of  the 
milk-producing  herds  are  being  continually  sold  for  slaughter  as  their 
usefulness  in  the  dairy  is  over,  and  an  examination  of  the  carcasses- of 
these  cows  would  serve  to  locate  the  existence  of  the  disease  in  many 
herds  where  its  presence  is  unsuspected.     Unfortunately  few  of  the 
animals  killed  in  the  small  slaughterhouses  are  inspected,  and  in  those 
cases  where  there  is  an  inspection  and  tuberculosis  is  discovered  it  is 
seldom  that  the  herds  from  which  they  came  are  traced  and  the  own- 
ers informed  of  the  discovery  of  this  disease.     In  any  effort  to  sup- 
press tuberculosis  it  is  almost  essential  that  information  of  this  kind 
should  be  obtained  and  an  attempt  made  to  persuade  the  owner  to 
adopt  proper  measures  for  getting  rid  of  the  contagion. 

3.  Measures  should  be  adopted  for  testing  herds  with  tuberculin 
without  expense  to  the  owners.     In  the  beginning  of  the  work,  at 
least,  this  should  not  be  compulsory,  but  it  should  be  made  to  the 
interest  of  the  owner  of  a  tuberculous  herd  to  have  it  tested  under 
the  auspices  of  the  State.     Apparently  it  would  also  be  wise  and  a 
great  aid  to  stockmen  for  the  State  to  test  herds  with  tuberculin  and 
certify  to  the  healthfulness  of  animals  from  all  those  herds  where  no 
reactions  occur.     At  present  it  is  a  difficult  matter  in  most  States  for 
the  breeder  or  dairyman  to  purchase  cattle  for  his  herd  with  any 
assurance  that  they  are  healthy.     He  may  have  them  tested,  but  there 
is  always  a  possibility  that  the}7  have  been  treated  with  tuberculin  a 
short  time  before  and  that  for  this  reason  they  have  not  reacted.    The 
loss  which  has  fallen  upon  the  breeders  of  the  country  through  the 
introduction  of  tuberculosis  in  their  herds  has  been  tremendous,  and 
it  appears  that  it  would  be  only  a  proper  aid  and  encouragement  to 
agricultural  interests  to  assist  breeders  in  obtaining  animals  free  from 
disease.     Not  only  would  this  encourage  farmers  to  enter  into  breed- 
ing operations  and  increase  the  value  of  the  industry  within  the  State, 
but  the  certification  of  breeding  animals  would  help  to  build  up  a 
market  in  other  States  for  breeding  animals. 


THE    REPRESSION    OF   TUBERCULOSIS.  93 

4.  In  order  to  encourage  the  owners  of  cattle  to  eradicate  tuber- 
culosis, States  should  allow  a  reasonable  compensation  for  the  animals 
which  it  is  necessary  to  slaughter  on  account  of  being  affected  with 
this  disease.     It  is  certainly  a  matter  of  great  importance  to  any  State 
to  have  its  herds  free  from  tuberculosis  and  its  animals  and  animal 
products  above  suspicion.      With  the  recent  demonstration   of  the 
communicability   of    animal   tuberculosis   to   man,   a   demonstration 
which  has  been  made  by  so  many  investigators  and  on  such  competent 
authority  that  the  fact  can  no  longer  be  questioned,  there  is  a  disposi- 
tion on  the  part  of.  sanitary  authorities  to  scrutinize  more  carefully 
those  animal  products  which  are  liable  to  be  infected.     It  is,  there- 
fore, becoming  every  day  more  important  for  every  State  to  repress 
tuberculosis  within  its  borders  and  in  that  manner  to  maintain  the 
reputation  of  its  animal  products.     Where  it  is  not  deemed  advisable 
to  provide  for  slaughtering  of  all  reacting  animals  with  sufficient  com- 
pensation from  the  State  to  make  this  measure  satisfactory  to  the 
stockmen,  the  State  may  provide  for  the  supervision  of  herds  handled 
according  to  the  Bang  method  or  some  modification  of  it.     For  the 
protection  of  its  own  citizens  who  consume  dair}7  products,  if  not  for 
the  protection  of  its  customers  in  other  States,  every  State  should 
make  some  arrangement  which  would  lead  to  the  removal  of  cows  with 
tuberculous  udders,  and  those  suffering  from  generalized  tuberculosis, 
from  herds  wyhich  supply  milk,  cream,  and   butter  for  human  food. 
This  much  is  essential  for  the  public  health,  but  it  would  be  wise  to 
go  further  and  provide  for  the  slaughter  of  all  cows  which  show  evi- 
dence on  physical  examination  of  being  affected  with  tuberculosis. 

5.  In  cases  where  cattle  owners  are  to  have  their  tuberculous  animals 
slaughtered  in  an  effort  to  free  their  herds  from  disease  the  State 
should  further  assist  them  by  disinfecting  or  at  least  supervising  the 
disinfection  of  the  contaminated  stables.     It  is  a  somewhat  difficult 
matter  for  persons  not  acquainted  with  the  practical  operations  of  dis- 
infection to  carry  out  this  measure  successfully,  even  after  they  have 
been  given  explicit  instructions.     It  is  impossible  to  'impress  suffi- 
ciently the  importance  of  thoroughness  upon  persons  who  are  lacking 
in  experience  in  this  line  of  work.     As  a  consequence  the  majority 
of  the  premises  disinfected   by  stockmen  without  the  assistance  of 
experts  are  imperf ectly  disinfected,  and  the  disease  breaks  out  again . 
among  the  animals  which  are  subsequently  introduced.     This  is  dis- 
couraging to  the  owner  and  serves  to  fix  the  impression  that  it  is 
impossible  to  eradicate  tuberculosis.     This  impression  is  already  wide- 
spread, but  it  is  essentially  wrong,  though  it  can  onl}7  be  removed  by 
object  lessons  in  the  eradication  of  the  disease  under  State  super- 
vision.    There  is  no  reason  why  tuberculosis  should  not  be  eradicated 
as  pleuro-pneumonia  was  eradicated.     The  contagion  is  more  wide- 
spread and  the  expense  would  be  greater,  but  there  are  no  inherent 
difficulties  to  prevent  the  success  of  such  an  undertaking. 


94  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

6.  When  a  herd  has  been  freed  from  tuberculosis  by  the  slaughter 
of  all  reacting  animals,  and  the  premises  have  been  properly  disin- 
fected, the  State  should  give  further  aid  to  the  stock  owner  by  testing 
without  expense  the  animals  which  he  desires  to  purchase  for  renew- 
ing his  herd.  This  measure  is  essential  to  the  success  of  any  plan  for 
lessening  the  prevalence  of  this  disease  or  eradicating  it.  The  expense 
of  testing  such  animals  is  almost  too  great  to  be  borne  by  the  individ- 
ual, and,  moreover,  private  tests  are  often  unsatisfactory  and  unreliable. 

FEDERAL  COOPERATION  FOR    THE   ERADICATION   OF 
TUBERCULOSIS. 

The  aid  of  the  Federal  Government  is  essential  to  the  success  of  any 
efforts  for  the  eradication  of  tuberculosis.  The  disease  may  be  held 
in  check  by  the  exercise  of  the  authority  of  the  individual  States,  but 
the  action  of  the  States  has  been  too  spasmodic  and  not  sufficiently 
general  and  harmonious  to  have  much  effect  upon  the  prevalence  of 
the  disease  in  the  country  at  large.  There  is  needed  a  systematic  plan 
of  repression  which  shall  be  generally  applied. 

At  no  time  has  there  been  more  public  interest  manifested  in  meas- 
ures for  reducing  the  mortality  from  tuberculosis  in  human  beings 
than  the  present.  Societies  for  furthering  such  measures  are  being 
formed  in  every  part  of  the  land  and  a  propaganda  of  education  is 
being  conducted  on  a  magnificent  scale.  It  has  already  been  shown 
that  human  tuberculosis  and  animal  tuberculosis  are  communicable 
between  persons  and  animals,  and  that  a  not  inconsiderable  proportion 
of  the  cases  of  human  tuberculosis,  and  especially  of  the  tuberculosis  of 
children,  is  caused  by  infection  from  animal  sources.  It  is  important 
to  the  success  of  the  efforts  against  human  tuberculosis,  therefore,  that 
the  continuous  infection  of  human  subjects  by  contagion  from  the 
lower  animals  should  be  prevented.  The  present  is,  consequently,  an 
opportune  time  for  the  Federal  Government  to  extend  its  aid  to  those 
States  which  are  willing  to  cooperate  for  this  purpose.  Not  only  would 
such  action  be  an  aid  to  agriculture,  but  it  would  at  the  same  time 
serve  as  a  protection  to  human  life. 

The  lines  of  work  which  the  Federal  Government  might  undertake 
may  be  formulated  as  follows: 

1.  Infected  herds  of  cattle  and  swine  could  be  readily  located  through 
the  meat-inspection  system  and  through  the  tuberculin  tests  that  might 
be  required  for  cattle  that  are  to  be  shipped  from  State  to  State  or  to 
foreign  countries.  The  meat-inspection  service  offers  a  magnificent 
opportunity  for  the  discovery  of  affected  herds  by  tracing  the  diseased 
animals,  which  are  discovered  daily,  back  to  the  farms  upon  which 
they  were  raised.  There  are  probably  but  a  small  proportion  of  the 
shippers  of  tubercular  hogs  who  know  that  they  have  this  disease  in 
their  herds,  and  the  evidence  of  the  fact,  which  is  discovered  in  the 


THE    REPRESSION    OF    TUBERCULOSIS.  95 

abattoirs,  is  never  brought  to  their  attention.  It  is  also  true,  as  is 
proved  by  examples  already  given  in  these  pages,  that  a  herd  of  cattle 
may  be  affected  for  a  long  time  and  a  large  proportion  of  its  members 
be  diseased  before  the  owner  becomes  aware  of  the  existence  of  tuber- 
culosis. A  systematic  effort  on  the  part  of  the  Government  to  dis- 
cover the  disease,  followed  by  the  communication  of  the  information 
both  to  the  owner  and  to  the  proper  State  authority,  would  prove  of 
great  value  in  furthering  this  work. 

2.  The  Government  might  also  very  properly  test  with  tuberculin 
breeding  animals  intended  for  interstate  shipment  upon  the  request 
of  the  owners  and  under  suitable  conditions.     By  doing  this  it  would 
be  preventing  the  interstate  shipment  of  diseased  animals,  and  at  the 
same  time  adding  greatly  to  its  resources  for  discovering  infected 
herds. 

It  would  be  a  most  important  step  to  test  breeding  herds  and  certify 
to  the  healthfulness  of  animals  from  those  which  proved  to  be  free 
from  disease.  There  must  be  a  large  proportion  of  American  herds 
which  are  not  affected  with  tuberculosis.  In  Denmark,  where  50  per 
cent  of  the  cattle  were  affected,  22  per  cent  of  the  herds  were  entirely 
free  from  the  disease.  In  the  United  States,  with  less  than  5  per  cent 
of  the  cattle  infected,  there  should  be  at  least  80  per  cent  of  the  herds 
in  a  healthy  condition.  This  being  the  case,  it  would  be  of  great 
importance  to  the  owners  of  the  vast  majority  of  herds  to  have  an 
inspection  and  to  receive  certificates  showing  the  healthfulness  of  their 
animals.  On  the  other  hand,  there  could  be  no  greater  inducement  to 
the  owner  of  a  diseased  herd  to  put  it  into  healthful  condition  than 
the  fact  that  his  herd  was  not  registered  as  free  from  disease  and  that 
he  could  not  obtain  certificates  as  to  the  health  of  his  stock. 

3.  It  is  doubtful  if  it  would  be  advisable  to  cooperate  with  State 
authorities  with  a  view  to  the  compulsory  slaughter  of  tuberculous 
animals.     This  work  has  succeeded  better  where  the  owner  has  volun- 
tarily participated  in  eradicating  the  disease;  and  it  appears  impor- 
tant that  he  should  be  interested  financially  m  accomplishing  this 
object.     The  Government  may  stimulate  this  interest  by  testing  his 
cattle  without  expense  and  by  giving  him  expert  advice  as  to  the 
measures  to  be  used  in  eradicating  the  disease.     It  may  also  agree  to 
compensate  him  liberally  for  any  animals  which  are  found  diseased 
and  which  it  may  be  necessary  to  slaughter.     But  it  probabl}T  should 
not  cooperate  with  the  States  on  the  lines  which  were  followed  with 
pleuro-pneumonia  and  foot-and-mouth  disease  with  a  view  to  compel 
him  to  accept  its  terms.     In  some  of  our  States  and  in  several  Euro- 
pean countries  the  repression  of  tuberculosis  is  being  conducted  with 
considerable  success  by  measures  which  are  voluntarily  accepted  by 
the  owners  and  which  secure  their  cooperation  not  only  in  getting  rid 
of  the  disease,  but  in  guarding  against  a  reinfection  of  the  herd. 


96  TUBERCULOSIS    OF    THE    FOOD-PRODUCINO    ANIMALS. 

A  departure  from  old  methods,  and  one  which  promises  valuable 
results,  has  been  made  by  the  Swedish  Government,  which,  since 
November  1,  1903,  has  been  engaged  in  forming  breeding  centers  for 
cattle,  one  of  its  objects  being  to  promote  the  industry  by  breeding 
animals  free  from  tuberculosis.  The  formation  of  breeding  centers 
for  improving  the  live  stock  of  certain  sections  of  the  country  has 
already  been  discussed  in  the  United  States,  and  such  a  movement 
might  well  receive  the  encouragement  of  the  Government  and  include 
within  its  sphere  the  development  of  herds  free  from  tuberculosis. 

Any  or  all  of  the  measures  enumerated  are  worthy  of  consideration 
in  this  connection.  The  prosperity  of  the  live-stock  industry  in  the 
United  States  will  depend,  for  years  to  come,  upon  foreign  markets 
for  animal  products.  If  we  can  compete  in  those  markets  in  price,  in 
quality,  and  in  reputation  for  healthfulness,  we  shall  continue  to  sell 
our  meats;  otherwise  we  shall  lose  the  trade.  It  is  not  an  age  when 
markets  can  be  held  without  striving  for  them ;  competition  is  fierce, 
and  alread}r  our  bacon  and  dressed  beef  trades  seem  to  be  yielding  to 
the  attacks  of  our  competitors.  Tuberculosis  in  our  herds  increases 
the  cost  of  producing  meat,  and  if  other  countries  outstrip  us  in  prac- 
tical work  for  its  eradication,  as  seems  probable  from  efforts  now  in 
progress,  that  fact  will  be  used  to  our  disadvantage. 

Fortunately  the  percentage  of  tuberculosis  in  our  herds  is  still  rela- 
tively low,  and  the  conditions  under  which  live  stock  is  raised  in  this 
country  are  favorable  for  the  eradication  of  disease.  When  public 
sentiment  favors  the  eradication  of  tuberculosis  in  animals  the  task 
will  not  be  found  an  impossible  one. 


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98  TUBERCULOSIS    OF   THE    FOOD-PRODUCING    ANIMALS. 

26.  See  Citation  11. 

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of  above  in  Jrn.  comp.  path,  and  ther.,  v.  18,  pt.  1,  p.  86-88.  Edinb.  and 
Lond.,  March,  1905. 

54.  HUTYRA,    FRANZ.     Schutzimpfungsversuche  gegen  die  tuberkulose  der  rinder 

nach  von  Behring's  methode.     Beit.  z.  exp.  ther.,  hft.  9,  p.  1-17.     Berl.,  1905. 

55.  HUTYRA,  FRANZ.     Schutzimpfung  gegen  die  tuberkulose  der  rinder.     Read   at 

Eighth  international  veterinary  congress,  Budapest,  1905. 

56.  THOMASSEN.     L'  immunisation  des  jeunes  bovides  contre  la  tuberculose.     Rec.  d. 

m&i.  vet.,  t.  80,  no.  1,  p.  5-19.     Paris,  January  15, 1903. 

57.  THOMASSEN.     Vaccination  contre  la  tuberculose.     Read  at  Eighth  international 

veterinary  congress,  Budapest,  1905. 

58.  KLIMMER,  M.     Bericht  viber  die  im  hygienischen  institut  der  koniglich  tierarzt- 

lichen  hochschule  ausgefiihrten  tuberkulose-arbeiten.  Berl.  tieriirztl.  woch., 
no.  37,  p.  465-169.  Berl.,  July  5,  1905. 

59.  Kocn,  ROBERT,  SCHCTZ,  W.,  NEUFELD,  F.,  and  MIESSNER,  H.    Ueber  die  immuni- 

sierung  von  rindern  gegen  tuberkulose.  Arch.  f.  wiss.  u.  prakt.  thierheilk., 
bd.  31,  hft.  6,  p.  545-575.  Berl.,  August  5,  1905. 

60.  BAS.SETT,  J.     Compte  rendu  de  1'experience  de  vaccination  antituberculeuse  de 

Melun.     Rec.  d.  med  vet.,  t.  82,  no.  23,  p.  815-819.     Paris,  December  15, 1905. 

61.  KOSSEL,  H.  and  WEBER,  H.     Wissenschaftliche  ergebnisse  der  bisher  im  kais. 

gesundheitsamt  angestellten  vergleichenden  untersuchungen  iiber  tuberkel- 
bazillen  verschiedener  herkunft.  Ztschr.  f.  tuberkulose  u.  heilstiittenwesen, 
bd.  7,  hft.  6,  p.  548-549.  Leipz.,  October,  1905. 

62.  Praktische  ergebnisse  der  neueren  forschungen  iiber  die  beziehungen  zwischen 

der  menschen-  und  tiertuberkulose.  Festgestellt  in  der  sitzung  des  unteraus- 
schussesfiir  tuberkulose  des  reichs-gesundheitsrates  vom  7.  Juni  1905.  Ztsch. 
f.  tuberkulose  u.  heilstiittenwesen,  bd.  7,  hft.  6,  p.  546-547.  Leipz.,  October, 
1905. 

63.  PEARSON,  LEONARD,  and  GILLILAND,  S.  H.     The  effect  of  tuberculosis  vaccina- 

tion upon  cattle  infected  with  tuberculosis.  Univ.  of  Penn.  med.  bull.,  v.  18, 
no.  12,  p.  30-35.  Phila.,  April,  1905. 

64.  BANG,  B.  Tuberculosis  of  cattle.    Pennsylvania  Department  of  Agriculture,  Third 

annual  report,  for  1897,  pt.  1,  p.  480-494.     [Harrisburg],  1896. 

65.  UJHELYI,  E.  Bekiimpfung  der  tul>erkulose  der  haustiere.     Read  at  Eighth  inter- 

national veterinary  congress,  Budapest,  1905. 

66.  RUSSELL,  H.  L.     The  history  of  a  tuberculous  herd  of  cows.     Wisconsin  Agr. 

Exp.  Sta.,  Bull.  78.     Madison,  Wis.,  August,  1899. 

67.  RUSSELL,  H.  L.     Tuberculosis  and  the  station  herd.     Maine  Agr.   Exp.  Sta., 

Fourteenth  annual  report,  for  1898,  p.  136-149.     Augusta,  Me.,  1899. 


001  134  941     2 


[Concluded  from  page  2  01  cover,  j 


CONTROL    AM)    ERADICATION'    OF    CONTAGIOUS    DISEASES. 


Inspectors  in  charye  of  district*. 


Dr.  U.  A.  Ramsay,  room  320,  Quincy  Building, 
Denver,  Colo.,  in  general  eharge  of  eradication 
of  scabies  oi'  sheep  and  eattle  in  (he  West. 

AlbuijUerqmvN.  Mex. — Dr.  Louis  Metsker,  room 
•1-1.  X.  T.  Annijo  Building. 

Denver,  Coli).— Dr.  Lowell  Clarke,  room  320, 
Building. 


Fargo,  X.  Dak.— Dr.  R.  H.  Treacy. 

Kansas  City.  Kan*. — Albert  Dean,  room  328,  Live 

Stock  Exchange. 
Salt  Lake  City,  Utah.— George  S.  Hickox,  room  21, 

Eagle  block. 


INSPECTION    OF    LIVE   STOCK    FOR    EXPORT. 

Inspectors  in  charge. 


Baltimore,  Md.— Dr.  H.  A.  Heclrick,  215  St.  Paul 

street. 

New  York,  X.  Y.— Dr.  W.  H.  Rose,  18  Broadway. 
Norfolk,  Va.— Dr.  G.  C.  Faville,  P.  O.  box  790. 


Philadelphia.  Pa.— Dr.  C.  A.  Schaufler,  134  South 
Second  street. 

Portland.  Me.— Dr.  F.  \V.  Huntington,  U.  S.  cus- 
toms ollice,  (irand  Trunk  R.  R.  wharf. 


INSPECTION    AND    QUARANTINE    OF    IMPORTED    ANIMALS. 


Athenin,  X.  J.  (for  the  port  of  New  York).— Dr. 
(ieorge  \V.  Pope,  suiierinteiident. 

Halt-thorp,  Md.  (for  the  port  of  Baltimore).— Wil- 
liam 11.  Wade,  superintendent. 


Littleton,  Mass,  (for  the  port  of  Boston). — Dr. 
J.  F.  Ryder,  inspector  in  charge,  141  Milk  street, 
Boston,  Mass. 


I  n. <••/><  ctors  on  the  Canadian  border. 


Calais,  Me.— Dr.  H.  T.  Potter. 

Carthage.  N.  Y.  —Dr.  \\.  S.  Corlis. 

Detroit.  Mich. — Dr.  L.  K.  Green,  care  Hammond, 

Standish  <fe  Co. 

Fort  Fairtield.  Me.— Dr.  F.  M.  Perry. 
Malone.  X.  Y.— Dr.  H.  D.  Mnyne. 
Xewport,  Yt.— Dr.  G.  W.  Ward. 


Ogdensburg,  N.  Y. — Dr.  Charles  Cowie. 
Orono,  Me.— Dr.  F.  L.  Russell. 
Port  Huron,  Mich. — Dr.  David  Gumming,  912  La- 
peer  avenue. 

St.  Albans,  Yt.— Dr.  C.  L.  Morin. 
Sank  Ste.  Marie,  Mich.— Dr.  J.  F.  Deadman. 


on  tJic  Mexican  border. 


Kl  Paso,  Tex.— Dr.  Thomas  A.  Bray. 

San  Antonio,  Tex. — Dr.  Joseph  W." Parker. 


San  Diego,  Cal. — Dr.  Robert  Darling,  care  Charles 
S.  Hardv. 


VETERINARY    INSPECTORS    STATIONED    ABROAD. 


Dr.  \V.  H.  Wray.  31  streatham  Hill,  London, 
S.W..  England,  in  charge  for  Great  Britain  and 
Ireland. 


Dr.  T.  A.  Geddes,  care  U.  S.  consulate,  Liverpool, 

England. 
Dr.  V.  A.  Norgaard,  Honolulu,  Hawaii. 


DAIRY    INSPECTORS. 


M.  \V.  Lang,  MO  Northwestern  Building,  Chicago, 

Robert  McAdam.olO  Northwestern  Building,  Chi- 

eago,  111. 
K.  A.  McDonald,  58  and  59  Downs  Block,  Seattle, 

Wash. 


W.   S.   Smarzo,   6   Harrison   street,    New    York, 

N.  Y. 

Li-vi  Wells,  l.aeeyville.  Pa. 
G.  M.Whitaker,  P.  O.  Box  1332,  Boston,  Mass. 


